Sunday, August 21, 2011

Costa Rica – Lizards around the house

We are fortunate to have numerous species of lizards all around us, so do not have to go far to see them. Most of the lizards in this post can be observed from our front veranda.

The Basilisk (Basiliscus basiliscus) is a species renowned for its ability to run on water. Juveniles are very common in this area, but the adults tend to spend most of their time near the river and are harder to get close to. During the day these lizards are active hunters, and move extremely rapidly to capture prey such as invertebrates and smaller lizards. At night however, they perch on foliage to sleep and we have found many of them hanging quite oblivious to approach on foliage around the yard and in the forest areas.

A young Basilisk, perched upon  a flower.

Another juvenile Basilisk

An adult male Basilisk

Common Anoles (Norops polylepis), true to their name are very abundant here. We were very excited to find a less common Green Tree Anole (Norops biporcatus) on the property. Anoles are well known for the territorial displays performed by males. They flash a colourful flap of skin beneath their throat known as a dewlap to warn off rival males.

A Common Anole with its dewlap exposed

The Green Tree Anole

Green Tree Anole

A close-up of the Green Tree Anole

We also have found Green Iguanas (Iguana iguana) right here on the property. The juveniles are a brilliant green, but lose the colour as they mature. The larger adults are grey-brown in colour and truly prehistoric in appearance. Green Iguanas are vegetarians and feed on the foliage of a variety of trees and shrubs, and will also feed on fruit. We spotted nine juveniles sleeping on one bush recently while were looking for invertebrates at night.

A juvenile Green Iguana

The head of a juvenile Green Iguana

One species which is found deeper in the rainforest is the Helmeted Iguana (Corytophanes cristatus), a species which can change its colour rapidly. I have been lucky enough to find two of these lizards while on our invertebrate collecting walks. These secretive lizards are ambush hunters and feed on a wide range of invertebrates. They apparently will also feed on Anole lizards.

A Helmeted Iguana

Helmeted Iguana

Monday, August 15, 2011

Costa Rica – Poison-dart frog

This spectacular little frog is the Granular Poison-dart Frog (Dendrobates granuliferus). Deanna found this gem on a rainforest trail during our nightly invertebrate collection walks.

Although this individual turned up at night, this species is primarily diurnal. The buzzing calls of the males can be heard from dawn until mid-morning.  They will also call late in the afternoon but fall silent when the bulk of the frogs here begin their activity after dark.

These frogs have potent toxins within their skin, an obvious strategy to avoid predation. Their common name is derived from its use by native hunters; they would extract the toxins and cover the tips of their darts, thus killing prey quickly with a small projectile. The species with the most potent toxin occurs in Columbia, where this practice was common.

Dendrobates granuliferus lays it eggs on the forest floor. After the tadpoles emerge, the adults carry them individually up into the trees and deposit them into small bodies of water, such as that held in bromeliads. 

Saturday, August 6, 2011

Costa Rica - Week 3 Moss Mantis

One of most amazing invertebrate encounters so far is the discovery of this ‘moss mantis’. We were looking for mantids in a patch of primary rainforest, but I didn’t expect to spot something as bizarre as this. I noticed a piece of moss hanging below a branch about five metre off the side of the trail we were on, but something struck me about its shape. When I stepped closer I thought I could make out a leg, then another, and once I spotted the antennae I knew I was looking at something pretty cool.

The 'moss mantis'. One of the most amazing mantids I have ever seen.

We haven’t identified this species yet, but it is truly a master of camouflage. It has the combined features and colours of moss and lichens which serve to hide its body form, and the result is stunning. I am quite amazed that I spotted it, even with years of experience in looking for such things.

This species is covered in bumps and flanges which  look incredibly like lichens and mosses.

Being a mantis it is naturally a predator, and one with complete ambush on its side. When it moves it rocks from side to side in very pronounced manner, just like the mossy tendrils hanging below the branches in its habitat. This enables it to move from one place to another without attracting the attention of predatory birds, lizards and frogs.
Even the eyes are superbly disguised.

Thursday, August 4, 2011

Costa Rica - Week 3 Boa Constrictor

We've been hoping to see a Boa, but didn’t quite expect to see one turn up in town. The young Boa pictured below fell out from beneath a car at the local service station as the car pulled away. It must have hitched a ride from somewhere and decided that was far enough.
The lucky young Boa Constrictor after its release in our backyard.
Our local assistant Steve was waiting for fuel and saw the snake appear, a lucky thing for the snake as the attendants were apparently a little fearful of it at first. I was waiting for Steve in the hardware store, and when he brought it in to me I was quite impressed with his bonus find at the gas station. If only Australian service stations would offer free reptiles with every 20 litres of fuel.

I took the snake back out to our rainforest abode, and released it after we’d all had a good look at it and taken a few pics.

It found a nice secure spot to spend the remainder of the day. 

Boa constrictors are the largest and heaviest snakes in Costa Rica. Although they have been recorded at growing to 5.5m, the largest specimens usually found are around 3.5m long. Boas are very robust snakes, so a specimen over three metres is a significant predator. Like pythons, they can feed on animals much larger than their head size. Costa Rican Boas feed on iguanas and other lizards, mammals including monkeys, and even deer. 

Monday, August 1, 2011

Costa Rica - Week 3

Here's a few of the species we have encountered recently. Have been having some fun with the camera too.

An unidentified praying mantis sitting on a red flower. Shot this  wide open to minimise the depth of field  and soften the background. 

The same mantis from a different angle. This species holds its raptorial legs out to each side while at rest.

A flame-bellied orb weaver,  Eriophora sp.

A bright coloured predatory katydid (Arachnoscelis feroxnotha). Apparently this is a relatively rare find - we have been lucky and have found five of them.

Arachnoscelis feroxnotha again. This species is an aggressive predator, catching other small invertebrates using the large spines to trap and hold prey before slicing it up with its massive mandibles.

A juvenile Basilisk lizard. This species can run on water.