Cobra-cega (Blind Snake)

March 10th, 2012 - 2:47 PM | Filed under Featured Photos | No comments

~12cm | January 8, 2012 | Tupaciguara, Minas Gerais, Brazil

I came across this small blind snake as it slowly wormed its way along a clear patch of ground next to a corn field. I thought it first it might be a worm, but something just looked a little odd about it. I picked it up and through my hand lens I could see it had scales. I also spotted its tongue darting in and out of its tiny mouth.

I didn’t know it then, but I was in the initial stages of chicken pox. All I knew was that I was feeling poorly and wasn’t motivated to take pictures in the field. I stuffed it in a small container for pictures later. The next day I took a few photos as I held it in my hand. I released it later that day in a field much like the one where I found it.

My brother-in-law’s family suggested it was a cobra-de-duas-cabeças (snake with two heads). It does indeed have a rounded off tail, making it difficult to tell which end is which. Some digging this morning though suggests that that name is more properly applied to a different type of reptile which isn’t a snake at all: amphisbaenians or worm lizards. In addition to not being able to easily tell which end is the head, they have the ability to move equally well both forwards and backwards. Probably the more likely common name for the critter I found is cobra-cega (blind snake).

It actually does have eyes, but they’re vestigial. It simply doesn’t need them since it mostly lives underground. Here’s the best closeup I could get of its tiny head. Too bad I didn’t happen to get one with the tongue flicking out.

Head showing vestigial eye

Blind snakes belong to three families in the  infraorder Scolecophidia. Some reading this morning suggests I probably can’t determine which family this one belongs to based on external characters alone.

I suspected at the time and confirmed this morning that they mostly feed on ants and termites.

 

Brown Blunt-headed Vine Snake

May 2nd, 2011 - 6:12 PM | Filed under Featured Photos | 5 Comments

January 19, 2011 | Armonia Nature Preserve, Limon Province, Costa Rica

As dusk arrived, I spotted this small vine snake, Imantodes cenchoa, descending a large tree. This species is chiefly arboreal, so seeing one near the ground was sheer luck.

A small snake, the head shown here is only 5mm wide. Overall I estimated this one to be less than a meter long, although they can grow to a bit more than that.

The head is much wider than the body. Thin as it may be, it can swallow prey ten times the width of its body. Nocturnal, these snakes hunt sleeping lizards, particularly anoles.

Head much wider than body

Also notable in this and related species are the scales along the middle of the back. These scales are many times wider than scales in adjacent rows. There’s a similar species, Imantodes gemmistratus, but its mid-dorsal scales aren’t quite as wide.

Wider mid-dorsal scales

With highly adapted skeletal and muscular structure, they have the ability to extend out up to half of their body. As shown here, they can reach out to nearby perches.

Body held aloft

Though possessing rear fangs with a weak venom, they rely on camouflage for defense. This one froze in place as soon as it became aware of my presence.

Reference:

A Guide to Amphibians and Reptiles of Costa Rica
by Twan Leenders

Eyelash Viper

March 26th, 2011 - 4:39 PM | Filed under Featured Photos | 2 Comments

~30cm | January 18, 2011 | Gandoca-Manzanillo NWR, Limon Province, Costa Rica

This eyelash viper, Bothriechis schlegelii, was on the side of a tree. A recent crypsis challenge asked readers to find it, which turned out to be fairly easy.

In the photo above, you can easily see the two scales above the far eye that give this snake its common name. No other Costa Rican snake has this distinctive feature.

I used my Canon 100mm macro combined with my Tamron 1.4x teleconverter to get some closeup shots, without getting too close myself. A handful of people die in Costa Rica every year from bites by this snake.

They are arboreal, as suggested by this one’s location.

Dorsal view | Note triangular head, much wider than body

I was in the area for a couple of hours, and the whole time it never budged. They are in fact sit-and-wait predators and may wait motionless for days. Prey includes the usual suspects: frogs, lizards, birds and small mammals.

I have to admit I was slightly disappointed that this one wasn’t the flashy yellow color of some other individuals. Color is remarkably variable. A mother may give birth (live, by the way) to a mix of yellow, green, or brown young, as above. This one does appear to be young, based on its size (estimated, obviously).

At the nearby Jaguar Rescue Center, I had the opportunity to see many more snakes of this species up close, safely behind glass. Have you ever heard that young snakes can be more dangerous than mature snakes? At the center, my guide explained why that might be. Venom is a precious resource for a snake. As snakes age, they learn to control how much venom is released during a strike. Adult snakes are more likely to deliver a measured amount of venom. They may even release no venom at all, a dry strike. So even though the venom doesn’t change as a snake matures, young snakes are more likely to release more of it, yielding a more dangerous bite.

In situ

Reference:

A Guide to Amphibians and Reptiles of Costa Rica
by Twan Leenders

Photo Details:

Canon EOS 60D
EF100mm f/2.8 Macro USM + Tamron 1.4x Teleconverter
Manual exposure, 1/250 sec, f/16, ISO 100
Canon MT-24EX Macro Twin Lite Flash

Canon EOS 60D
EF100mm f/2.8 Macro USM + Tamron 1.4x Teleconverter
Manual exposure, 1/250 sec, f/16, ISO 100
Canon MT-24EX Macro Twin Lite Flash

Canon EOS 60D
EF-S18-55mm f/3.5-5.6, Shot at 18 mm
Auto exposure, Shutter priority AE, 1/160 sec, f/5.6, ISO 800
Canon MT-24EX Macro Twin Lite Flash

Crypsis Challenge #9 Reveal

February 28th, 2011 - 6:56 PM | Filed under Crypsis Challenges | 2 Comments

Looks like all commenters easily spotted the snake in this photo.

January 18, 2011 | Gandoca-Manzanillo NWR, Limon Province, Costa Rica

It’s about a third of the way from the top right. Here’s a closer shot from roughly the same angle.

Closeup of eyelash viper on tree trunk

As Andrea J determined, this is an eyelash viper, Bothriechis schlegelii. It’s difficult to pick up an ecotourism brochure in Costa Rica and not see a picture of the yellow variety of this species.

Look out for a separate post on this individual with many more photos.

Oh, and don’t worry, I kept a respectful distance. This encounter reminded me why I always carry around a teleconverter.

Young Rattlesnake

December 30th, 2010 - 11:04 AM | Filed under Featured Photos | 3 Comments

January 31, 2010 | Tupaciguara, Minas Gerais, Brazil

I haven’t yet driven MG-223 that leaves Tupaciguara in the direction of Araguari at night without seeing a snake crossing the road. Here’s the most recent one I spotted, which I assume is a young rattlesnake. It’s small, maybe 6 inches or so, and it looks like it has a button at the end of its tail.

My real dilemma when I spot one is whether or not to stop and risk getting hit by another vehicle. At any rate, I’m definitely in a hurry to get a photo and get back up to speed.