Bosque del Cabo – Looking at the Rarely Seen   3 comments

Felipe del Bosque Blog April 1st 2013

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Mud Mosaic

Initially there had been no sign of the weather changing with the hot and dry conditions continuing throughout the week.  The creek is still flowing but the forest floor is now starting to crack intensely forming a series of polygonal reticulations.  The lawns have lost a lot of their vibrant green color and there are large scorched patches of parched grass which have become crispy and brittle underfoot.  Some of the plants on the forest edges are now turning yellow and wilting.

One small glimmer of hope is that over several nights there has been a mass of dark cloud gathering.  By early evening there was the occasional sprinkle but in total precipitation it did not amount to much, little more than a damping of the top surface of the ground.  The rains did not materialize despite the heavy dark cloud cover but it is still a little too early in the season.

Dione juno

Not Sticking Out.

Most people are familiar with walking sticks, the insects not the ambulatory aid.  All of the different species basically have the same morphological design; a long body, legs and antennae.  When they are located in amongst the vegetation they are almost impossible to see.  When stationary they hang motionless from a twig with the antennae close together and held out straight from the front of the body along with the front pair of legs.  The illusion is that of just one more spindly twiglet.  For this reason, despite the relative abundance, they are rarely seen.  You can be staring directly at one but the deception is flawless you won’t see it.

Walking sticks belong to the Order: Phasmatodea or Phasmids which consists of approximately 2,500 species divided into six families.  They are distributed globally but a large percentage exists in the neotropical forests.  They are plant eaters and closely resemble the vegetation on which they are feeding.  Some of them, particularly the males have wings and so if you pay too close attention the twig you are looking at may take to the air and disappear into the distance.  As well as the amazing cryptic form of the phasmids, they can also enhance the impression of being a plant part with behavioral displays such as swaying back and forth to mimic movement in a breeze.

Walking Stick

Mini Beaver

Sometimes while walking around the gardens you may see some plants that have the stem neatly bitten through.  Closer inspection reveals a cut not too dissimilar to the way a beaver gnaws through and fells a tree using that perfectly executed circular grooved cut.  That might lead you to assume the culprit could be a smaller rodent practicing the same destructive tendencies on a mini scale.  It sounds plausible but it is not actually what is happening.  The villain in this case is smaller still and has six legs.  Not only that but it sports two very long antennae.  It is a species of Long-horned Beetle, Family: Cerambycidae.  As with so many other beetles it is a Herculean task for many specialist coleopterists to identify them to species level but the stunning alternate orange and black segments making up the long curved antennae are enough to give me at least an identification to family level of the mystery mini lumberjack.

Long-horned Beetle

Hanging Around at Night

The Three-toed Sloth, (Bradypus variegatus), is a common mammal on the grounds of Bosque del Cabo.  It is one of those creatures that fascinate people simply because it is such a unique looking animal.  Quite often it is the first mammal people enquire about seeing when they arrive at the lodge.  They are plentiful on the grounds but not always the easiest mammal to find.

The sloth lives almost 100% of its life up the top of trees.  It is a leaf eater and leaf does not yield much energy so much in the fashion of the Howler Monkeys of the neotropics or Koala Bears of Australia they do not move much and when they do it is not very far.  The Three-toed Sloth has a territory of about 40 trees but they return frequently to a home tree called a modal tree.  The diet is not that varied especially considering the diversity of tree species growing in any one given area.  They prefer to eat younger leaves which can be found at the end of the branches.  They are aided in reaching these by having proportionately long arms in comparison with body length.

One of the best trees in which to spot a sloth is the Cecropia tree.  These have an open crown which makes viewing more accessible.  The Cecropia is also a good place for the sloth to sunbathe.  It has a very low basal metabolism and very slow passage of food through the alimentary canal, sometimes up to a month.  The sun’s energy heats up the sloths body and helps speed up digestion.  In a temporal or period of low sunlight levels the sloths can die of hypothermia.

The sloth descends to the ground every 7 days or so to defecate.  There are several theories as to why they might do this but the most plausible is the fact that the sloth being such a slow mover if it were to defecate from the tree tops, any potential predator would spot the fresh feces, look up and there is its meal sitting directly above.  That descent for a toilet trip is hazardous to a slow moving creature so once a week it takes its life in its hands, climbs backwards down a tree trunk, bores a hole in the earth with its short stubby tail and poops.  It covers the material to stop it being easily located then ascends to the tree tops to wait another week before coming back down again.

Different individuals have different food preferences in terms of the leaves they eat.  This preference is conferred on a young sloth by its mother.  It inherits the taste for certain leaves by tasting the leaf fragments on the lips of the mother.  As different individuals have a specific group of tree species from which they are taking leaf, a small area with high tree species diversity can support a larger number of sloths than it otherwise would.

This female sloth had been hanging around in the vicinity of the mango orchard near the restaurant for weeks.  Every few days it would change its location to a new tree.  One night it was hanging from a vine about 9 feet above the ground.  It didn’t appear to be doing anything in particular and didn’t seem like it was going anywhere.  I went and got the camera and took a series of pictures then departed to leave the creature to figure out what it was going to do next.

Three-toed Sloth

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

Hide and Seek

There are some animals that may be present in large enough numbers to be considered common but are not seen that often because they don’t want to be seen.  They may live in inaccessible areas or make themselves scarce upon your approach.  Two such reptiles turned up last week.

The Southern Bromeliad Boa, (Ungaliophis panamensis), is a dwarf boa not reaching dimensions anywhere similar to its more famous relative the Boa Constrictor.  It is regarded as being not very abundant but I find this species more frequently than some of the other snakes at Bosque.  This individual turned up in the Boa Bar early one evening.

These boas can be found from high in the trees to ground level in the forest.  They are normally active from dusk to dawn.  The diet consists of frogs, small lizards and small rodents.  They are very shy and placid snakes more inclined to hide their heads under the body rather than bite if disturbed.

Southern Bromeliad Boa

Basilisks are renowned for their ability to run across the surface of the water which gives them their alternative name of Jesus Christ Lizards.  They are diurnal lizards and generally can be found in the vicinity of water such as creeks, ponds, mangroves and estuaries.  As soon as you approach they will stand up on their back legs and take off running bipedally across the surface of the water.  What allows them to do that is the fact that the toes on the hind feet are long and fringed which spreads the weight of the lizard over a much wider surface area and consequently not breaking the surface tension.

This was a male Common Basilisk, (Basiliscus basiliscus), that I found sleeping in a palm near the restaurant one night.  When fully grown the males are approximately 3 feet long.  The males have a crest on the back of the head and a high fan that runs the length of the body and then the tail.  The females are smaller and unadorned.  The adults feed on a large variety of food including pond vegetation, insects, lizards, snakes, rodents and small birds.  The juveniles are more restricted to a diet of smaller arthropods.

Common Basilisk

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 0.01 ins.  Total Weekly Rainfall 0.08 ins

Average Daily Rainfall 0.3 mm.  Total Weekly Rainfall 2.0 mm

Highest Daily Temp 94°F.  Lowest Daily Temp 76°F.

Highest Daily Temp 34.3°C.  Lowest Daily Temp 24.7°C.

Species List for the Week


  • Mantled Howler Monkey
  • Spider Monkey
  • White-faced Capuchin Monkey
  • Common Tent-making Bat
  • Western Red Bat
  • White-nosed Coati
  • Agouti
  • Alfaro’s Pygmy Squirrel
  • Red-tailed Squirrel
  • Three-toed Sloth
  • White-lipped Peccary


  • Mealy Amazon
  • Red-lored Amazon
  • Scarlet Macaw
  • Great Curassow
  • Broad-winged Hawk
  • Mangrove Black Hawk
  • Roadside Hawk
  • White Hawk
  • Golden-naped Woodpecker
  • Lineated Woodpecker
  • Streak-headed Woodcreeper
  • Black-hooded Antshrike
  • Chestnut-backed Antbird
  • Short-billed Pigeon
  • White-tipped Dove
  • Rufus Piha
  • Long-billed Hermit
  • Stripe-throated Hermit
  • Blue-crowned Manakin
  • Red-Capped Manakin
  • Spectacled Owl
  • Chestnut-mandibled Toucan
  • Cherrie’s Tanager
  • Bright-rumped Atilla
  • Buff-rumped Warbler
  • Dusky-capped Flycatcher
  • Golden-crowned Spadebill
  • Great Kiskadee
  • Great Tinamou
  • Black-throated Trogon
  • Slaty-tailed Trogon
  • Violaceous Trogon
  • House Wren
  • Black Vulture
  • Turkey Vulture


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


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


  • Agraulis vanillae
  • Anartia Fatima
  • Anartia jatrophae
  • Caligo atreus
  • Colobura dirce
  • Cupido comyntas
  • Dione juno
  • Dryas iulia
  • Eueides lybia
  • Eurema albula
  • Heliconius erato
  • Heliconius ismenius
  • Heliconius sapho
  • Hermeuptychia hermes
  • Mechanitis polymnia
  • Mesosemia zonalis
  • Morpho cypris
  • Morpho helenor
  • Morpho menelaus
  • Philaethria dido
  • Phoebis argante
  • Phoebis sennae
  • Pierella helvina
  • Pierella luna
  • Pyrgus oileus
  • Pyrrhogyra crameri


  • Alamandra  cathartica Flowering
  • Alpinia purpurata Flowering
  • Apeiba tibourbou Fruiting
  • Arachis pintoi Flowering
  • Arundina graminifolia Flowering
  • Attalea rostrata Fruiting
  • Bauhinia variegata Flowering
  • Brosimum utile Fruiting
  • Caryocar costaricense Flowering
  • Cascabella thevetia Flowering and Fruiting
  • Citrus spp  Fruiting
  • Clusia rosea Flowering and 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 citrifolia Fruiting
  • Ficus insipida Fruiting
  • 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 Fruiting
  • 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
  • Zammia sp Flowering




3 responses to “Bosque del Cabo – Looking at the Rarely Seen

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  1. Loved learning about the sloth.


  2. Your bird lists are helping me to familiarize myself with my Birds of Costa Rica book. So looking forward to my trip!


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