Archive for the ‘Marine Toad’ Tag

A New Season of Discovery   10 comments

Philip Davison. nature diaries. Osa Peninsula. Costa Rica.

After a five week period away from the Osa Peninsula I am back to carry out another year of research.  For the past sixteen years I have been monitoring populations of both butterflies and amphibians in the forests of Cabo Matapalo on the tip of the Osa Peninsula in South West Costa Rica.  I collect the daily weather data and compare changes in amphibian populations against precipitation and butterflies populations against temperature in an effort to evaluate how or whether climate change effects the fauna of a tropical rain forest.

Marine Toad. Amphibians. Osa Peninsula. Costa Rica.

Marine Toad, (Chaunus marinus)

As I live in the forest and can be found constantly walking the trail systems, camera in hand, it provides ample opportunity to photograph the diversity of life that surrounds me.  I am generally photographically prepared for small things so unless I am going out specifically to capture images of mammals or birds then my photographic galleries generally consist of reptiles, amphibians, all manner of arthropods as well as any plant and fungi features that catch my eye.

Savage's Thin-fingered Frog. Frogs

Savage’s Thin-fingered Frog, (Leptodactylus savegei)

This blog acts as an expanded form of my nature diaries which are simply daily recordings on Excel spreadsheets.  I enjoy sharing my experiences with those who read my blog and over the years the number of subscribers constantly increases.  If you are a first-time reader, then welcome and I hope you enjoy the content and the photos.  I am not a professional photographer but I do try and take the best composed shots I can.

Banana Frog. Wet Season.

Banana Frog, (Dendropsophus ebreccatus)

The blog also allows visitors to the area an insight of what they might expect to see in their absence or when they arrive as well as providing a small amount of information about the natural history of the organisms I feature.  I try to post one blog a week but sometimes time constraints means there may be occasions when this is not possible.

Small-headed Frog. Pond life.

Small-headed Frog, (Dendropsophus micracephalus

For me the year does not begin on the January 1st but rather on my return to the area in November.  At this time of year we should be moving out of the main rainy season, which is what caused me to leave for a month or so, and into the dry season.  There is no exact date and sometimes the rains hang on until December while other times the sun has started to shine constantly by mid-November.  Anyway, here we go with the opening blog of the 20016/17 season.

Olive-snouted Treefrog. Philip Davison

Olive-snouted Treefrog, (Scinax elaeochrous)

First things first.  November normally heralds the ending of the rainy season.  Sometimes the wet period may continue into December but by now we are looking towards a drying of the forest.  Not so this year.  This has been, without doubt, the wettest November I have recorded in 17 years, 185 inches of rain fell in that 30-day period.  The area was briefly closed down as bridges were not crossable, roads were not passable and the local town of Puerto Jimenez and its attendant landing strip were closed due to being under water.  This may bode well for the coming dry season when for 4/5 months the area receives little or no rain whatsoever but at the moment the forest floors have rivulets with running water everywhere.

Red-eyed Green Tree Frog. Costa Rica

Red-eyed Green Tree Frog, (Agalychnis callidryas)

The daily torrential downpour has made wildlife spotting rather difficult.  It is neither easy to see or hear anything in those conditions.  In the inter deluge periods I have been out searching for whatever I could find and it may come as no surprise that the amphibians most certainly have enjoyed the excess water.  All the usual members of the pond community have been out calling; Banana Frogs, Small-headed Frogs, Red-eyed Green Tree Frogs, Parachuting Red-eyed Green Tree Frogs, Savage’s Thin-fingered Frog, Marine Toads and Masked Smiliscas.  Even the largest tree frogs in Costa Rica, the Milky Frogs have been coming out, which is unusual this time of year.  Away from the pond the Tink Frogs and Fitzinger’s Rain Frogs call as soon as the sun sets.  Here are some photographs of the amphibians you may be lucky enough to see if you visit the Osa Peninsula now.

Parachuting Red-eyed Green Tree Frog. Torrential Rain.

Parachuting Red-eyed Green Tree Frog (Agalychnis spurrelli)

Tink Frog. Frog chorus.

Tink Frog, (Diasporus diastema)

Gladiator Frog. Mud puddle nest

Gladiator Frog, (Hypsiboas rosenbergi).

Bolivian Frog. Foam nest.

Bolivian Frog, (Leptodactylus bolivianus)

Masked Tree Frog.

Masked Smilisca, (Smilisca phaeota)

Philip Davison is a Biologist, Photographer and Writer based in Costa Rica.

Here Comes the Rain Again   1 comment

Felipe del Bosque Blog June 2nd 2013

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Water World

Now the rains have started and with a ferocity of a force that has been pent up for 5 months.  Over the past few weeks there were occasional showers which had   brought some light relief to the parched ground and thirsty plants but the small amount of precipitation was not really making an impact on the soil at depth.  Over recent days the skies have been dark and heavy with brooding clouds always threatening to douse the area in rain.  The threats eventually changed to action, the clouds broke and down came the deluge accompanied by bright streaks of lightning that lit up the black night sky.  Thunder was rumbling around for hours on end in the immediate vicinity and for days over a wider area as a portent of what was about to happen.

Lush Forest

The first real week of rain produced over 20 inches.  The upper layers of the soil softened after months of cracking up in dry conditions resulting in sticky mud adhering to the shoes of walkers on the trail.  The mystifying annual drying of the creek occurred as it does each year with the onset of the rains.  Those initial downpours are followed by an immediate disappearance of water from the water channels which had already been low in volume to start with.  The heavy rains were followed by lighter but more constant rain.  Now the sunny days were few and far between.  After a week of these conditions the creek began to flow once more.  But two days without rain would see it run dry once again.  It will take several more weeks before the water issues from the springs in sufficient quantity to see the creek water levels rise.

Towards the end of the week the rains lessened in both duration and volume.  We finally had a weekend with the sun shining brightly and a clear blue sky.  Let’s see how long that lasts.

Special Cases

There was one Puma, (Puma concolor), sighting last week.  A couple walking on the Creek Trail were initially concerned by the fact that they had stumbled upon a female Puma sleeping in the middle of the path.  Her presence froze them to the spot as they tried to recall the protocol for situations such as these.  There was no cause for alarm. The cat roused, lazily got to its feet and, although somewhat disturbingly for them, walked towards them, then turned and headed of unhurriedly into the forest.  The guests did manage to get a reasonable picture given their preoccupation with considering a hasty get away.  The picture revealed that the Puma was “Half-tail” a female that has been resident here for many years and raised several sets of cubs with the Bosque forests.

It was also nice to see this week the at least one of the White-lipped Peccaries, (Tayassu pecari), is walking around the grounds of Bosque.  It passed in front of the restaurant without stopping one day not long after lunchtime.  It did not seem too happy to be out in the open and made its way very quickly back into the forest by Cabina Mariposa.

There are a couple of Three-toed Sloths, (Bradypus variegatus), that can be seen in several localities near the restaurant.  One female seems to have her territory in and around the mango orchard.  She can regularly be seen in the mango trees or in one of a variety of different taller trees in the same area.  Yet another female can be seen at the tops of the trees on the Creek Trail immediately behind the bar.  The Three-toed Sloth normally only has a territory consisting of about 45 individual trees so they never venture too far from any one spot.  The trick is to find them and that is not always easy.  But if one is spotted then everyone at the lodge will be talking about it and if the conversation is taking place not long after the sighting then the chances are it will still be there for all to see.

Three-toed Sloth

Loopy for Fruit

One question frequently asked by guests to the lodge is whether the animal life shuns the rain and takes shelter while it is raining.  This is a rain forest and the animal life here is adapted to living in these conditions.  If they were to hide from the rain, which is what is does here 7 months of the year, then that would be unfeasibly long sleep.

Everything is out and about as normal, the rain has by no means hindered the animal activity.  The vegetation is drawing up the water and the now washed leaves cleansed of the layer of dust and dirt that accumulated during the dry season are looking vibrant, lush and green.

At the moment there is a lot of Spider Monkey, (Ateles geoffroyi), activity.  Troupes can be seen swinging through the tree tops, noisily making their way to some tree laden with fruit.  Several species of Fig, (Ficus spp), are currently providing an abundant crop for a variety of animal life on which to gorge themselves.

There are a number of Queen’s Crape Myrtle Trees, (Lagerstroemia speciosa), scattered throughout the garden areas of Bosque.  These are currently in flower as well as producing fruit which the Toucans appear to be enjoying.  Not only are the myrtles fruiting in front of the restaurant but there are a variety of different palm species that are also attracting the attention of the toucans.

Toucans are such distinctive birds so it is very unlikely that anyone visiting Bosque would not know what they were looking at even though they may not have seen one in the wild.  For many years the Guinness breweries featured them as part of their promotional advertising.  Children are more likely to have seen them consuming Fruit Loops.  Although they don’t have a fondness for breakfast cereal they most certainly are fruit eaters.  The only species of toucan to be found on the Osa Peninsula and consequently at Bosque del Cabo is the Chestnut-Mandibled Toucan, (Ramphastos swainsonii). That characteristic long bill is an adaptation allowing the toucan to reach its food.  Fruit normally occurs at the end of branches which won’t support the weight of a large heavy bird such as the toucan.  Despite its appearance the bill is hollow and very light.  This allows the toucan to sit on a part of the branch that will support its weight while reaching out to pluck the fruit.  Toucans are gulpers; they toss the fruit in the air and swallow it without masticating.  They do occasionally supplement their diet with protein by taking an assortment of small animals including rodents, reptiles and other birds’ eggs and chicks.  This occurs more frequently during the nesting season, (January-June), when the rapidly growing toucan chicks need protein in order to develop.  This time of year they can be seen in small flocks which may become periodically noisy with a loud call that resembles a rusty pulley that needs a drop of oil.

The Queens Crape Myrtle is a decorative non-native ornamental that graces the gardens of many properties in Costa Rica.  The tree originates in the Old World tropics of South East Asia being found as far south as Northern Australia. The name refers to the crumpled purple petals which resemble crape paper.  Within the gardens of Bosque del Cabo the Queen’s Crape Myrtle poses no problems but in open wet pastures it can become invasive.

Queen's Crape Myrtle Flower

Queen's Crape Myrtle Fruit

This individual toucan, one of a noisy flock, that I photographed from below was not entirely sure of my intentions and kept turning its head one way and then the other as it cast a watchful eye over me.  It did not seem too disturbed as it carried on preening itself for a while before taking to the air and flying off to a neighboring tree.

Chestnut-mandibled Toucan

One of the large Costa Rican Royal Palms, (Attalea rostrata), is both flowering and fruiting in front of the restaurant at the moment.  The inflorescence is a huge bract bearing countless thousands of tiny yellow flowers.  These are hugely attractive to many insects which come in massive numbers to feed on the short term nectar supply.  There is the perpetual buzz of bees in particular around the flowering bract.  As the flowers are pollinated the spent blossom falls to the ground producing a small floral carpet around the base of the palm.

Attalea rostrata

The fruit that subsequently develop are large woody “nuts”.  As the palm nuts ripen they draw large numbers of Spider Monkeys and Capuchin Monkeys, (Cebus capucinus).  A good many of the fruits fall to the ground where there is another set of diners waiting to feed on the banquet dropping from above.  The large caviomorph rodents commonly seen around the grounds, the Agouti, (Dasyproctus punctata), gather around the base of the trees.  Turkey Vultures, (Cathartes aura), which are normally associated with a diet of carrion also congregate to feed on the fallen fruit.


Turkey Vulture

Keep Your Head

There are two species of caracara the inhabit the grounds of Bosque del Cabo and it is normally fairly easy to see them both in the vicinity of the restaurant.   The Yellow Headed Caracara, (Milvago chimachima), has been a Bosque resident for many years now.  They breed readily and the adults are quite often seen with vociferous demanding youngsters constantly screeching at them for food.  The young birds are dependent upon the adults for several months until they acquire the relevant skills needed to hunt for themselves.  The adults can be as noisy as their offspring producing very high pitched screeches.

Yellow-headed Caracaras have only been recorded in Costa Rica from 1973.  They are birds of open pasture and scrubland.  Progressively as the trees were felled in Costa Rica and the forests were turned into grazing lands the Yellow-headed Caracaras found their way north from neighboring Panama.

Yellow-headed Caracara

This individual caught my eye when it was determined to catch something in the grass. I moved in as close as I could without disturbing it although it was aware of my presence and kept an eye on me, its attention was more focused on a Halloween Crab, (Gecarcinus quadratus), trying to escape being eaten.  This was a young bird still with the last remnants of juvenile plumage.  The bird would grab the crustacean in its bill and throw it a short distance, not exactly sure how to avoid the pincers.  It had not quite perfected its technique, which would come with time.

The Crested Caracara, (Caracara cherriway), is another falcon, slightly larger than its yellow-headed cousin, that is normally found in more open areas.  Some 3 or 4 years ago we had several pairs make their way into the grounds of Bosque del Cabo from the pastures a couple of miles down the road.  Conditions here obviously suited them because they have been here ever since.  They can be found most days strutting around on the lawns in front of the rest looking for grubs or whatever morsel may have discarded by another predator.  Both species of caracara are carrion feeders but would defer to the much larger vultures of which there are many individuals onsite.

Crested Caracara

The caracaras belong to the Falcon Family: Falconidae.  There is another raptor, the Roadside Hawk, (Buteo magnirostris), from the Hawk Family: Accipitridae, that is very common around the grounds of Bosque del Cabo.  They can be seen sitting on the lower branches of the trees in the more open garden areas waiting for a meal to walk by which is generally one of the smaller ground living lizards, (Ameiva spp).  Although the Roadside Hawk has pleasing good looks with its grey head and shoulders, brown barred chest and vivid yellow eyes, cere and legs, it still has that less than melodious shriek of a call that is typical of many raptors.

Roadside Hawk

Philip is a biologist, writer and photographer as well as the onsite naturalist guide at Bosque del Cabo Rainforest lodge on the Osa Peninsula, Costa Rica.

Photo Feature

Bursting into Life

The rains have brought about an explosion in amphibian numbers, both individuals and species.  A trip to the pond at night will reward the visitor with a spectacular frog show.  Covering the Water Lettuce and Water Hyacinth are large numbers of calling male Banana Frogs, (Dendropsophus ebreccata).  These small yellow frogs with mottled skin resembling the skin of a banana call with a high pitched “eek, eek”.  The larger females will join the males selecting a mate on the quality of his call.  They lay their eggs on the vegetation floating on the water surface where they develop for 7 or 8 days before the now formed tadpoles wriggle free to complete their development in the water.

Banana Frog

Slightly higher you can hear the constant “chuck chuck” of the Red-eyed Green Tree Frogs, (Agalychnis callidryas).  It doesn’t take much searching before you will locate the gaudily colored calling male that is the darling of the Costa Rica advertisers.  Just as with the Banana Frogs the larger females seek out the calling males, they pair up and then visit the pond about three times over the course of the evening.  Each visit the female absorbs a lot of water through her skin, fills her bladder and then they go to the underside of a leaf overhanging the pond where she will lay a clutch of about 50 eggs.  Once again the tadpoles develop over the course of a week, the egg mass liquidizes and they slip into the water to complete their development.

A few weeks ago, along with the first rains, the Milky Frogs, (Trachycephala venulosa), arrived at the pond in phenomenal numbers.  This explosive breeding episode happened intermittently for several weeks and then they disappeared to where they had come.  Now there are one or two males seen in the higher levels of the plants growing around the pond but now sitting in quiet contemplation of all the other activity taking place around them.

Milky Frog

The Marine Toads, (Chuanus marinus), which are normally found everywhere around the grounds have started to congregate around the pond too.  The males, the mating call of which sounds like a mini jack hammer, sit around the pond edge at night waiting for the much larger females to turn up.  The Marine Toads pair up and lay their long strings of eggs in the water.  Marine Toads are the largest of the Costa Rican amphibians with the females sometimes attaining 3 lbs in weight.

Marine Toad

The second largest amphibians in Costa Rica are Savage’s Thin-fingered Frog, (Leptodactylus savagei).  These are handsome mottled smoky colored frogs that can also be found in large numbers around the pond at night.  The males, which are easily distinguished from the females by their huge front legs, start to call with an incessant “whoop whoop”.  The females respond to the calls and as they approach are grabbed by the males in a strong embrace until they are ready to spawn.  When the female spawns, the male fertilizes the egg mass, then using his powerful and muscular hind legs, whips the eggs up with mucus from his body and water from the pond into a white froth.  Once again the tadpoles develop in the froth for about a week, the froth then dissipates and the tadpoles exit this foam nest into the water to complete their development.

From the largest to possibly one of the smallest and paradoxically loudest of the frogs at Bosque del Cabo, the Tink Frog, (Diaspora diastema).  These tiny frogs, less than an inch in length are noticeable by their absence for 5 months of the dry season.  Like so many other amphibians, once the rains arrive they appear as if by magic in huge numbers.  With the Tink Frogs you are very rarely going to see them but you most certainly will hear them.  At the onset of the wet season the male Tink Frogs call producing the characteristic ping, not unlike the chime of a small metal bell, which can be heard all night every night for 7 months of the year.  Quite often the males call from within a hollow trunk or branch so that when you approach the sound and are quite sure you are looking directly at its origin, you can’t see what is making it because it is hidden within.

Where there is a short term abundant supply of food then it won’t take long for the predators to arrive.  Some of the major predators on frogs and their eggs are snakes.  All year round you will find Cat-eyed Snakes, (Leptodeira septentrionalis), somewhere around the pond at night.  Their location depends upon the time of year.  Now that the frogs are out in force engaged in a reproductive frenzy there is plenty free protein going in the form of frogs eggs and it is this easy food source that the Cat-eyed Snakes relish and feed upon.  They can sometimes be seen in anything up to 50 in number cruising over the leaves with their heads beneath searching for the eggs of the Red-eyed Green Tree Frog.  Lower down they will be searching for the Banana Frog eggs but should an unwary frog present itself as a target the snakes will take that too.

Cat-eyed Snake

During the dry season the Cat-eyed Snakes will be more commonly found around the pond edge.  Even though the main period of frog reproduction takes place throughout June, July and August there will always be 1 or 2 breeding outside of the season.  There is less of a supply but the snakes, now also lower in numbers, sit and pick of the froglets as they emerge from the water.

Much larger in size and much more of a concern are the Terciopelos, (Bothrops asper).  These nocturnal pit vipers are found in the dry season down by the creeks at night long after the sun has set.  This time of year they can be seen sitting by the pond where they will envenomate and consume the larger amphibians.  Although they are not always seen, there are plenty of rodents and small opossums by the pond which also provide a perfect meal for these beautiful but deadly predators.


Last year seems to have been a particularly successful breeding year for the Black and Green Poison Arrow Frogs (Dendrobates auratus).  They are everywhere; hopping around on the forest floor, all around the restaurant, on the deck of my cabin and even in my shower.  They are diurnal frogs and a short walk behind the bar on the Creek Trail should reward you in a very short space of time with the sightings of several of these small neon green and black frogs.

Black and Green Poison Arrow Frog

Down in the damp creek beds the second species of dendrobatid that Bosque has, The Golfo Dulce Poison Arrow Frog, (Phyllobates vittatus), can be seen.  The increase in precipitation has brought about an increase in activity and the soft but persistent trill of the male can be heard in most of the creeks.

Text and Photographs are taken from the forthcoming book:

The Natural History of Bosque del Cabo by Philip Davison

Temperature and Rainfall

Average Daily Rainfall 0.23 ins.  Total Weekly Rainfall 1.59 ins

Average Daily Rainfall 5.8 mm.  Total Weekly Rainfall 40.4 mm

Highest Daily Temp 85°F.  Lowest Daily Temp 74°F.

Highest Daily Temp 29.1°C.  Lowest Daily Temp 23.1°C.

Species List for the Week


  • Mantled Howler Monkey
  • Spider Monkey
  • White-faced Capuchin Monkey
  • Common Tent-making Bat
  • Western Red Bat
  • Crab-eating Raccoon
  • White-nosed Coati
  • Kinkajou
  • Agouti
  • Vesper Rat
  • Nine-banded Armadillo
  • Three-toed Sloth
  • White-lipped Peccary


  • Orange-chinned Parakeets
  • Red-lored Amazon
  • Scarlet Macaw
  • Great Curassow
  • Pale-billed Woodpecker
  • Crested Caracara
  • Roadside Hawk
  • Yellow-headed Caracara
  • Streak-headed Woodcreeper
  • Black-hooded Antshrike
  • Chestnut-backed Antbird
  • Short-billed Pigeon
  • Long-billed Hermit
  • Stripe-throated Hermit
  • Red-Capped Manakin
  • Chestnut-mandibled Toucan
  • Fiery-billed Aracari
  • Cherrie’s Tanager
  • Bright-rumped Atilla
  • Golden-crowned Spadebill
  • Great Kiskadee
  • Great Tinamou
  • House Wren
  • Riverside Wren
  • Masked Tityra
  • White-collared Seedeater
  • Black Vulture
  • Turkey Vulture


  • Barred Ameiva
  • Cat-eyed Snake
  • Central American Smooth Gecko
  • Central American Whiptail
  • Clawless Gecko
  • Common Anolis
  • Common Basilisk
  • Four-lined Ameiva
  • Golfo Dulce Anolis
  • Litter Skink
  • Litter Snake
  • Mediterranean House Gecko
  • Terciopelo


  • Banana Frog
  • Black and Green Poison Arrow Frog
  • Fitzinger’s Rain Frog
  • Golfo Dulce Poison Arrow Frog
  • Marine Toad
  • Milky Frog
  • Red-eyed Green Tree Frog
  • Savage’s Thin-fingered Frog
  • Tink Frog


  • Dryas iulia
  • Eurybia lycisca
  • Glutophrissa drusilla
  • Heliconius erato
  • Heliconius ismenius
  • Heliconius sapho
  • Hermeuptychia hermes
  • Magneuptychia libye
  • Morpho helenor
  • Morpho Menelaus
  • Phoebis argante
  • Siproeta stelenes
  • Strymon megarus
  • Urbanus simplicius
  • Urbanus tanna


  • Alamandra  cathartica Flowering
  • Alpinia purpurata Flowering
  • Apeiba tibourbou Fruiting
  • Arachis pintoi Flowering
  • Arundina graminifolia Flowering
  • Attalea rostrata Fruiting
  • Bauhinia variegata Flowering
  • Caryocar costaricense Fruiting
  • Cascabella thevetia Flowering and Fruiting
  • Citrus spp  Fruiting
  • Clusia vallerii Fruiting
  • Cocos nucifera Flowering and Fruiting
  • Crestentia alata flowering and Fruiting
  • Costus speciosus Flowering
  • Couroupita guianensis Flowering and Fruiting
  • Dypsis lutescens Flowering and Fruiting
  • Etlingera elatior Flowering
  • Ficus insipida Fruiting
  • Garcinia madruno Fruiting
  • Gustavia brachycarpa Flowering
  • Heliconia chartacea Flowering
  • Heliconia latispatha Flowering
  • Heliconia pogonantha Flowering
  • Heliconia psittacorum Flowering
  • Heliconia rostrata Flowering
  • Hibiscus rosa-sinensis Flowering
  • Hymenaea coubaril Fruiting
  • Hymenocallis littoralis Flowering
  • Inga spp Fruiting
  • Ixora coccinea Flowering
  • Lantana camara Flowering and Flowering
  • Lagerstroemia speciosa Flowering
  • Morinda citrifolia Fruiting
  • Musa acuminate Flowering and Fruiting
  • Nephelium lappaceum Fruiting
  • Pachira quinata Flowering
  • Piper auritum Flowering and Fruiting
  • Piper nigrum Fruiting
  • Piper umbellatum Flowering and Fruiting
  • Pleiostachya pruinosa Flowering
  • Plumeria rubra Flowering
  • Psychotria sp Fruiting
  • Stachytarpheta frantzii Flowering
  • Symphonia globulifera Fruiting
  • Voschia ferruginea Flowering
  • Zammia sp Flowering





Marine Toad: Beauty or the Beast

The sun had set some hours ago and now everyone was gathering in the dining room for the evening meal.  It had been a tiring day.  There were those who had walked the trails,  trekking along paths through the forest, battling against the oppressive heat and humidity in search of exotic neotropical wildlife.  Others had taken on the task of walking down to the beaches to soak up the sun and play in the surf.  Wherever the adventure had taken them, one thing they now had in common was that they had stoked up an appetite.  Everyone was famished.  The buffet table was laid out.   There was a range of dishes, each one complementing the other and all looking delicious.  Everyone filled a plate, sat down and the meal began.

Female Marine Toad, (Rhinella marina), sitting at edge of pond.

Female Marine Toad, (Rhinella marina)

Unbeknownst to the diners, they were being watched.  Gazing out at the scene from nooks and crannies all around the restaurant were eyes, not human eyes but rather those of another creature waiting for one feast to end and for another to begin.  They would not emerge while the lights were ablaze, but those lights are important for what would happen later.  While the diners ate, talked and laughed their way through the evening they were unaware of something happening around them.

From the depths of darkness in the surrounding forest, insects were being attracted, like the proverbial moth to a flame, towards the bright and beckoning lights illuminating the restaurant.  Once there, they would settle.  Normally using the light from celestial bodies to navigate, these flying insects had unwittingly been drawn to an artificial source of light and having arrived there were fooled by its brightness into thinking it was day.  So there they stopped.  The eyes were still watching though and the watcher was waiting.

Presently the meal and following conversations ended.  Sated and ready for bed, the guests proceeded to leave for their cabins, while the waiters cleared the tables.  The time was getting closer.  Eventually with the floor swept, the dishes washed and the tables set for the following day’s breakfast, the staff left the building.  The final action was to turn off all the lights.  Now something stirred, eyes blinked, patiently waiting for the security that no human had been left behind.

After a few minutes of silence and total darkness, movement could be detected.  A small squat creature squeezes from behind books in the library and comes hopping across the floor.  From under the low levels of the shelves, from the surrounding flower borders more of the creatures emerge.  They now gather in the empty restaurant and tonight’s second sitting begins.  The new diners have dry, warty skins and hop across the tiled floor to the areas of the recently turned off lights.  These are Marine Toads, (Rhinella marina), and they have come to eat the insects that were attracted to the lights over the course of the early evening.

The name Marine Toad is derived from the fact that you can find them down on the beach but they are not tolerant of salt water so you won’t find them in the sea.  They are not generally found in the forest but rather around human habitation.  Also, they do not always need the stimulus of movement to feed, as do most amphibians, so they can take food from pet bowls that have been left overnight.  Males will grow to about a year old, females will continue to grow to about four years old.  At four years, the female Marine Toad can be anything up to 3 lbs in weight, making this the largest of the Costa Rican amphibians.

They are very poisonous; the two main poison sacs, the parotid glands, appear as large expanded areas , one behind each eye.  These are the toads that were introduced into Australia in the 1930’s to clear the cane beetles from the cane fields.  The Australian predators had never come across them before, fed on them, were poisoned and died.  That left Australia with a much bigger problem than it had originally, a massive explosion in the mouse and rat populations.  They have been introduced to Hawaii, Florida, Australia, Papua, and some Caribbean Islands, all resulting in the same problems, not the fault of the toad as it is humans that take them there.

No-one in Australia thought to talk to a biologist about that biological control technique, as the cane beetles they were introduced to feed upon live at the top of the cane stems whereas the toads live at the bottom.  From that time to this, despite the Australian government introducing measures to reduce the populations of Marine Toads, it has continued to be an ecological disaster of  the countries own making.

Marine Toads return to the water to reproduce and each female can lay upto 13,000 eggs.  That many eggs with no predators means the Marine Toads can get out of control very quickly.  In Costa Rica the Marine Toad is native, it does have predators.  Opossums will catch them, split them open and leave the skins while some snakes are immune to the toxin.  Not too many will initially take a look at a toad and appreciate its beauty, but just before you vent you disgust have one more look deep into that eye, perhaps then you will see something different.

Close up of the head of a Marine Toad, (Rhinella marina).

Marine Toad, (Rhinella marina). Close up.

There have been recorded instances of people trying to make a meal of this toxic amphibian, the consequences of which ended with dire results.  The following passage describes the ill-fated attempt by a family to cook and eat this particular amphibian.

“About 10 a.m. all four members of the family began to vomit……The mother and sister were prostrate, and their lips and fingers were blue; pustules had formed on the sister’s lips.  The abdomens of the mother and the sister appeared bloated and their bodies were hot and quite rigid.  They were pronounced dead by 12 noon…..The Peruvian intern in charge believed death was due to ‘cardiac seizure”, preceded by respiratory difficulties”.

The milky white toxin secreted from pores in the skin is Bufotoxin which causes massive vaso-dilation and poisoning of the cardiac muscle tissue.  So Marine Toad pie is off the menu.



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