Saturday, March 31, 2012

Readers Write In: What is this Snake? Part II

I was very impressed by the readership a couple weeks ago when I asked everyone to chime in regarding their thoughts on a mystery snake I was sent to identify, so I thought we should make this a recurring feature.

I just received the following e-mail.

"I can't ID this snake positively. I think its a Black Racer. I live about 60 miles north of Miami. I know it's not poisonous but need to prove it to all my 'All snakes are poisonous and need to be killed' friends.


OK, so there you have it. We are under pressure to identify this animal as a harmless creature. Let's see if we can do so. As before, include your identification in a comment below and be specific regarding how you came to your conclusion. Last time we had a couple of skilled biologists participate; this time I want to hear from everyone else too, even if there are already some answers listed. Don't be shy; even "experts" make mistakes (if you don't believe me, just look at all the reminders I get in the comments section of this post)

What is this animal?

Tuesday, March 20, 2012

Humans Can Be Bizarre, Too

There never seems to be much of a shortage of articles or blogs about how some animals are truly bizarre, weird, or otherwise outrageous. These discussions never resonated with me. Animals have incredible and diverse strategies, behaviors, shapes, and sizes that allow them to persist and thrive in their environment. It would never occur to me to think of these animals as weird.

No, for the truly strange, we must look inward. How weird is it that humans hold annual celebrations in which the main focus is rounding up and killing animals for entertainment? How bizarre is it that this is socially acceptable and encouraged?

These thoughts occurred to me recently as I was reading a number of newspaper articles promoting, excuse me, reporting on the events associated with the Sweetwater, Texas Rattlesnake Roundup. How else can we explain why skinning a recently decapitated and still-squirming animal is considered, "laugh-inducing"? Is it really that much fun to cut up an animal, feel its still-beating heart, and then slap your bloody handprints on the wall? If so, I have to admit that I have been looking for entertainment in entirely the wrong places. I think a beating snake heart is much more interesting when the snake is still wearing its skin.

I wrote last week about how the organizers of the Sweetwater Rattlesnake Roundup raised their rattlesnake bounty this year in hopes of gathering more snakes. It didn't work. As this press-release, excuse me, newspaper article, notes in relation to a rattlesnake-eating contest, it was once again a below-average year. Whether the roundup organizers are correct in attributing low rattlesnake numbers to weather patterns, there seems to be no arguing the fact that there have been less rattlesnakes crawling around Texas lately. I guess this means people should try harder to round up what's left? After all, those bloody handprints on the wall aren't going to get slapped on themselves.

Now that is what I consider bizarre.

Wednesday, March 14, 2012

Readers Write In: What is Eating this Dead Snake?

Today I received the following e-mail from a reader in Florida:

"We had a 5 foot snake in our back yard which our yard man killed and then left it.  My husband did not get the chance to discard of it and today when we went out to remove it there is something that is pulling it into the ground.  It was a good size snake and it fits right into the hole.  We saw the tip of the legs of the animal doing the pulling and it almost looked spider or crab like.  We live in Merritt Island, Fl and are across the street from a small wooded area which sits along the river. Between us and the river is also a very busy road.  I am wondering if you have any idea what kind of creature could be living underground and likes to eat a dead snake.  I hope you can come up with an answer for us because we are stumped.  Thanks for your time.

Brooke H.
Merrit Island, Florida"

This was a surprising question for me because I was not asked to identify the dead snake! After receiving this e-mail, I immediately thought of carrion beetles. This group of invertebrates has some unique reproductive strategies. Some of these insects, after locating a dead animal, will bury the carcass and lay their eggs on it. When the eggs hatch, the young are provided with a ready food source. This information was fresh in my mind because just a few months ago I conducted some background research on the topic. Super-naturalist (and fellow blogger) Dirk Stevenson recently observed a number of dung beetles (which may just eat dead things and not necessarily lay their eggs in them) feeding on a watersnake carcass and we concluded it was the first time this behavior had been observed between these species.

Dung Beetles Feeding on a Watersnake, courtesy D. Stevenson
I contacted Dirk to confirm my suspicions and he agreed that the culprit could have been been a carrion beetle. But, he suggested I focus on the fact that the animal appeared crab-like. There are, after all, crabs that love to eat dead things.

I followed Dirk's advice and my research quickly led me to the Blue Land Crab, Cardisoma guanhumi, which can be found throughout much of coastal Florida. These large crabs can live relatively far from the ocean (but often inhabit areas near river banks) and they inhabit deep tunnels (up to six feet, according to this link). Basically, the crabs make their tunnels as deep as needed to reach water, which pools on the bottom. Although they live much of their lives in these tunnels, Blue Land Crabs return to saltwater areas to breed. 

Blue Land Crabs feed largely on plant-matter, but they are omnivorous and are known to drag dead things back to their burrow, where they can eat in safety. I think a large Blue Land Crab would be very interested in a fresh snake carcass and I believe this is what Brooke observed in her backyard. Do all the Florida crustacean biologists agree?

Blue Land Crab (Creative Commons License)


Want to Learn More? Check out the Following Scientific Articles:

Gifford, C. (1962). Some Observations on the General Biology of the Land Crab, Cardisoma guanhumi (Latreille), in South Florida Biological Bulletin, 123 (1) DOI: 10.2307/1539516

D. J. Stevenson, D. A. Steen, & M. Wallace (2012). Nerodia erythrogaster erythrogaster (Red-bellied Watersnake). Necrophagy by dung beetles (Scarabaeinae). Herpetological Review

Friday, March 9, 2012

Friday Roundup-Western Diamondback Shortages and Sailfish Taking the Bait

An Eastern Diamondback Rattlesnake from Georgia
A Scarcity of Rattlesnakes in Texas? This week, a newspaper article about the Sweetwater (Texas) Rattlesnake Roundup caught my eye. Rattlesnake roundups out West are a little different from the roundups in the southeastern United States. First of all, there are more of them (there are only two left in the Southeast) and second of all, they collect different species; specifically, the Western Diamondback Rattlesnake, Crotalus atrox, is the animal most often captured for Texas and Oklahoma roundups.

It is generally thought that, in contrast to the Eastern Diamondback Rattlesnake, Crotalus adamanteus, there are plenty of Western Diamondbacks. That's why I was surprised to read that this year, the organizers of the Sweetwater Roundup have increased the bounty they are paying on snakes. They say that there were few rattlesnakes brought in last year, and the increased bounty will offer a greater incentive for people to catch more animals. This turn of events reminded of an economic phenomenon related to rare species. When an animal becomes rare, the value of that animal increases and people will pay more for it, whether it's for medicine, food, or as a pet. The more the animal is worth, the more incentive have for people to catch it, and on and on. It's a cycle of increasing value and rarity until the animal is extinct, or nearly so. Now, it is true that wildlife populations fluctuate in size over time, so I don't know for sure that this cycle of rarity and economics is what's happening with the Western Diamondback, but don't say I didn't warn you.

Me with a NY Snapper
The Iconic Snapping Turtle: Ted Levin writes an excellent article about the natural history and ecology of the Snapping Turtle, Chelydra serpentina, in New England. The article features an interview with one of my favorite authors, David Carroll; his writing had a profound impact on how I perceive the natural world and, in particular, wild turtles.

The Aquatic Ballet of Predator and Prey: I recently found, thanks to Blogfish, an incredible video of two dozen sailfish (I'm not sure of the species, there are two potentials) feeding on a school of baitfish. Using slow-motion technology, we are able to see both the defensive maneuvering of the small fish and the hunting strategy of the huge predators. The sailfish strike their intended prey with their bills, stunning them and making them easier to catch with their mouths. Amazing stuff.

Interested in learning more? Check out these scientific articles:

L.A. Fitzgerald, & C.W. Painter (2000). Rattlesnake commercialization: long-term trends, issues, and implications for conservation Wildlife Society Bulletin, 28 (1), 235-253

Brook, B., & Sodhi, N. (2006). Conservation biology: Rarity bites Nature, 444 (7119), 555-556 DOI: 10.1038/444555a

Monday, March 5, 2012

Readers Write In: What Is This Snake?

As you know, I welcome reader questions. The most common question I receive involves identifying snakes found in and around homes  (I previously presented a compilation of these e-mails here). The most recent entry arrived in my inbox last week. I think I have solved the case, but I would like a second (or third, or fourth) opinion.

"Can you help me ID this snake? I found my cat playing with it, I assume that she killed it but I do not know that for sure. I'm not the type to kill snakes, and I'm not too scared of them. I would like to know if I could possibly have a 'litter' of them in my house though.  I think it is a hognose, but I'm not sure.


Brent L.

So that you all have the same information I did when I identified the snake, Brent informed me (in response to a couple follow-up questions) that he was located in northeastern Mississippi and there is a small pond located about 500 feet from his house.

Okay distinguished readership, what say you? Please identify the species of snake in the above picture by leaving a comment below. In your comment, please describe how you came to your conclusion. 

Friday, March 2, 2012

Friday Roundup-A Tribute to Leap(ing animals) Year and High Frequency Primates

In Honor of Leap Year: Deep Sea News presents this compilation of marine creatures leaping out of their oceanic habitats. Photographers with good timing captured these rare moments, allowing us to see animals like tuna, squid, and sharks, in a different light. The picture of the breaching Sperm Whale, Physeter macrocephalus is stunning. No, the last photograph is not real.

What's the Frequency Kenneth? The world we experience is not necessarily an accurate representation of the way the world actually is. No, I'm not getting philosophical on you, I am trying to make the point that the way that we experience things is based on our senses, including sight, smell, taste, sound, and touch. More specifically, the way we experience things is based on the limits of what our eyes, nose, etc. can do. And, we all know that some animals have better, or different, abilities to sense things. Dogs are famous for their ability to follow scents, vipers can detect infra-red heat, mantis shrimp can see colors we cannot, for some examples. In other words, we are missing out on the world around us. Sarah Buckleitner writes on the Wild Mammal Blog about a recent paper that describes how tarsiers (a type of Asian primate) communicate using sounds that we cannot hear, in ultrasound.


Want to learn more? Check out these scientific articles:

Ramsier, M., Cunningham, A., Moritz, G., Finneran, J., Williams, C., Ong, P., Gursky-Doyen, S., & Dominy, N. (2012). Primate communication in the pure ultrasound Biology Letters DOI: 10.1098/rsbl.2011.1149

Cronin, T., & Marshall, N. (1989). A retina with at least ten spectral types of photoreceptors in a mantis shrimp Nature, 339 (6220), 137-140 DOI: 10.1038/339137a0