Costa Rica; where the Americas meet #2. Animals, frogs and scales.

A little while ago, following a visit to this special country, I posted here an introduction to it. You might want to start with that post, though it isn't essential to reading this one; you will however find there more information on most of the localities mentioned here. My original intention was to put up two posts on animals of Costa Rica - one on the birds, the other (this one) on 'the rest'. However, when I was about three quarters of the way through this one I realised that it was just too long and unwieldy, even before I'd got to the mammals! So I've gone back and split this post in two, in the hope that some of you will find your way through both rather than giving up in exhaustion. (Though I confess that I did then take the opportunity too to slip a few more photos in...)

Here then is an introduction to some of the numerous and fascinating frogs and reptiles of the country; the tropics abound in these groups which are fascinating and often very photogenic. It's mostly a 'photo essay', with most of the information in the picture captions. For no good reason - other than 'why not?' - I'm going to start with some frogs, then go on to reptiles.  

The first five frog species belong to the very large and widespread tree frog family Hylidae.

Crowned Tree Frog Anotheca (or Triprion) spinosa, Tapirus Lodge, central mountains.
A spectacular arboreal frog found in scattered locations in Central America, it breeds
in above-ground puddles in tree hollows or bromeliad leaves. The female
provides unfertilised eggs as food for the growing tadpoles!

Golden-eyed Tree Frog (it goes by several different names though) Agalychnis annae,
in the grounds of the Hotel Bougainvillea on the outskirts of the capital, San José.
It is a highly Endangered species, living only in the heavily populated and
cultivated central valley; this population in the hotel grounds is apparently
the only one in the vicinity.

Red-eyed Tree Frogs Agalychnis callidryas on the other hand are very
common in Central American rainforests. The spotlight has messed with
its glorious colours, and the eyes in particular, which are really a glowing bright red.
We were there in the rainy season and, like these two, many frogs were engaged
in producing even more frogs!

Hourglass Tree Frogs Dendropsophus ebraccatus. The smaller male in this case lacks the
hourglass shape on the back of most of the species; the top of it can be seen on the female's
head. They can be found throughout Central America and as far south as Ecuador.

Masked Tree Frog Smilisca phaeota, Tapirus Lodge. A common (and rather
winsome) tree frog found throughout the moist lowlands and lower mountains,
and from Honduras to Ecuador.

The other well-known tropical American frog family is that of the poison dart frogs, Dendrobatidae, with some 170 species. These are diurnal frogs, often brilliantly coloured, a very few of which were used by Native Americans to extract poison for blowpipe darts. The alkaloid toxins (which are very potent) are produced by the frog from chemicals in their insect diet, and stored in skin glands for use in protection against enemies. Their striking visibility is a warning. Two species are common in Costa Rica, though not found everywhere there.

Green-and-black Poison Dart Frog Dendrobates auratus. It is found in southern
Central America to Colombia, but in Costa Rica only on the southern Pacific coast.
This one was in rainforest in Carara National Park. It really looks like porcelain!

Strawberry Poison Dart Frog (also known as Blue Jeans Frog!) Oophaga pumilio,
until recently included in the larger genus Dendrobates. This frog can be found
in almost any Costa Rican lowland forest or plantation. It has a range of colour
variants, some of which lack the blue legs, and others are not red at all.
Their range is centred on Costa Rica, and extends into Nicaragua and Panama. This one
was at the wonderful La Selva Research Station, in the Caribbean lowlands.

Finally, before I get too carried away with these frogs, a nod to one of the many other families present.

Foam frog Leptodactylus sp. at Esquinas Lodge in the Piedras Blancas NP
in the far south near the Pacific coast. This is a substantial group of mostly large
frogs, and I'm not able to identify this one further, though would welcome
suggestions. Eggs are laid in a protective bed of foam on the water surface
and the tadpoles fall into the pond below when they hatch.

Reptiles are numerous and diverse throughout the tropics, and Costa Rica is no exception. We encountered a good selection of both snakes and lizards, so let's meet some of them.

 

Some of the snakes were non-venomous...

Northern Cat-eyed Snake Leptodeira septentrionalis, Esquinas Lodge.
This little snake (found from the far south of the US to Costa Rica) hangs around
ponds, hunting frogs and their egg masses.

Common Snaileater  Sibon nebulatus, Tapirus Lodge. Another small snake that
lives on slugs and snails, extracting these from the shell with specially adapted jaws.

... others less so.

Hog-nosed Pitviper Porthidium nasutum, Tapirus Lodge. This venomous little snake was
on the concrete by the stopping platform at the top of the 'aerial tram' ride through the rainforest
canopy. The young fellow staffing the platform reckoned it was 'just there'. Well, maybe.
Normally they lie still in leaf litter awaiting a meal of a small mammal, frog or lizard.

Eyelash Pitviper Bothriechis schlegelii, rainforest canopy walk, Monteverde. This is a surprisingly
common snake in Costa Rica, nearly always encountered on branches, which may be nearly
at ground level or high in the canopy (like this one, which is peeping out at us through the
coils). There is also a bright yellow version, which I've not seen. It waits patiently - for
weeks sometimes - for birds, small mammals or lizards. Young ones tend to be close to
the ground, and ascend the trees as they get older and switch prey from mostly frogs.

Here is a closeup of the same species, close to the ground, displaying its 'eyelashes'.

Young Eyelash Pitviper, Tapirus Lodge. The 'eyelashes' are of course no such thing, but
modified scales. Their purpose is unclear but it is suggested by those who've studied them
that they help to break up the outline of the distinctive head to better hide from potential prey.

Fer-de-Lance Bothrops asper, Carara NP. This can be a huge snake, up to 2.5 metres long, and
highly venomous. It was curled up in the dark under a park bench by a well-used walking track.
The park staff had simply put a ribbon barrier up for the duration of its stay to prevent us from
taking a rest there. (The vertical pupils distinguish it from the similar False Fer-de-Lance
Xenodon rabdocephalus which has round pupils.)

Many of the lizards encountered - and they are abundant - belong to a cluster of families that include the iguanas and anoles (and the Australian dragons).

Green Iguana Iguana iguana, San Isidro. This is a common big lizard (to more than
1.5 metre long) found naturally from Mexico to southern Brazil. It comes in a range
of colours in addition to green, and is a adept at climbing, swimming and burrowing.
Fortunately for small animals it is mostly vegetarian.

Spiny-tailed Iguana Ctenosaura similis, Carara NP - a group of these big iguanas
was running the carpark when we first visited. They also climb trees well, but have an
affinity for rocky areas...

... as evidenced by this young one in the north at Rincon de la Vieja, displaying
the bright green colouration typical of juveniles.

There are three common species of the extraordinary basilisks in Costa Rica, and throughout most of Central America (plus another in north-western South America). The aspect of them which is most often remarked upon is their ability - especially of smaller individuals - to run several metres on the surface of water, flailing their hind legs very fast and spreading their long toes to distribute the weight.

Green Basilisk Basiliscus plumifrons, Tortuguera on the Caribbean coast. This is a spectacular
animal and quite common, especially along waterways.

Brown Basilisk Basiliscus vittatus in the grounds of Esquinas Lodge.
This one is only found (but very commonly) on the Pacific side of Costa Rica.

Green Spiny Lizard Sceloporus malachiticus, Savegre Valley on the Pacific slopes.
This a common lizard in the mountains; indeed we first saw it basking at some 3400 metres
above sea level, above the tree line in conditions that we reckoned were uncomfortably cold.

The anoles, in the same general grouping, are abudant, mostly small quick lizards found on tree trunks and branches.

Slender Anole Anolis limifrons, in the rain at Esquinas Lodge. This little fellow was
very agile, leaping between leaves.

Bridled Anole Anolis frenatus, seen at night at Tapirus Lodge. My impression is that
most anoles are active in the daytime; this is also large for an anole, at around 15cm long.

Another commonly seen Costa Rican lizard group is the whiptails (or ameivas, from a former genus name), in the family Teidae. They are very common along forest tracks, on logs and in the litter. They are long-tailed and quick and some are brightly coloured. This one however was in our cabin, living on and in the totally superfluous bed doona that was on the floor.

Central American Whiptail Holcosus festivus, La Selva Research Station.

Geckoes were less obvious than I might have expected, but maybe that was just me. Here is a rather lovely daytime species which was dining out too, on one of the wooden supports of an outdoor restaurant.

Yellow-headed Gecko Gonatodes albogularis, a widespread species of drier
tropical forests, here at Caño Negro in the northeast.

I find it surprising that there are only four species of freshwater turtle in Costa Rica (though I have no real reason to be surprised, I must admit). This appears to be the commonest one, but is only found on the Caribbean side.

Black River Turtles Rhinoclemmys funerea, beneath the pedestrian bridge across the
Puerto Viejo River at La Selva Research Centre.

Finally there are two species of crocodilians, one quite common, the other definitely not.

Spectacled Caiman Caiman crocodilus, in the wetlands of Caño Negro.
This smallish caiman (generally less that two metres long) is found thoughout Central
America and the north of South America. It keeps to itself in the rivers and
wetlands, mostly being active at night, and hunting fish.

American Crocodile Crocodylus acutus, Tarcoles River on the central Pacific coast. This is about
the only place in Costa Rica that this magnificent animal - up to six metres long and weighing almost
 a tonne for very large males - is still relatively common. Here there is a thriving
business in running crocodile tours (very reminiscent of the Daintree River in Queensland).
There is also a constant stream of  tourists disgorged at the end of the highway bridge over the river
to walk on the narrow footpath, with heavy traffic seemingly only centimetres away,
to gaze down at the crocodiles which are usually lying below, facing the current to harvest
unwary fish. Overall there are probably no more than 3000 in the wild, from Florida
to northern South America.

And you may well be relieved that that's all for today (though not too relieved I hope....). Back soon to complete this series with some invertebrates and mammals. The birds can then wait for a slightly later date, while I post on something a bit closer to home. Thanks for accompanying me!

NEXT POSTING THURSDAY 2 NOVEMBER

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