Monday, January 30, 2012

Monday's Specie in Peril---African Slender Snouted Crocodile

File:Crocodylus cataphractus faux-gavial d'Afrique2 .JPG

 The African Slender-Snouted Crocodiles (Crocodylus cataphractus) are native to fresh water habitats in Central and Western Africa. Their common name comes from their extremely long, slender mouth. They have many common names including Long-snouted West-African crocodile, African gharial, Panzer crocodile, Long-nosed crocodile, African sharp-nosed crocodile, Faux gavial africain, Loricate crocodile, Subwater crocodile, Khinh, Cabinda. This is a relatively small to medium sized crocodile reaching lengths up to 12 feet or a bit more.

They are generally a solitary species of crocodile and only come together during the rainy season for breeding purposes. After mating the female will build a nest of plant material on the banks of rivers. About one week after constructing the nest mound, the female will lay between 13 and 27 very large eggs within the nest. In approximately 3 1/2  months the young begin to hatch. Which is a much longer incubation period than most crocodilians. The young will chirp from within the nest inside the eggs, this is referred to as pipping. The female will help the young out of their eggs and out of the nest. This particular species does not defend the nest or young as aggressively as other female crocodilians.

Predation by other animals is probably not an issue with this species because of their long incubation process and the fact that they have very sharp teeth and will defend themselves. Although soft shell turtles are known to eat the young crocodiles. The litter sizes are usually small and very little is known about their range, even in areas where they are considered common not much is known about them. They are however believed to be in decline, primarily due to over hunting, and habitat loss is exacerbating the problem. Very little enforcement is used in protecting this species and many areas till allow the harvest of this species, despite its dwindling numbers.

Thursday, January 26, 2012

Watersnake Rescue

The most incredible thing happened today. I got a phone call at work from a man who told me that his sister and her husband were clearing weeds and brush out of a ditch in front of their home. There was some water in the ditch at one end and they noticed  something under the ice. It looked snake-like. Upon closer inspection, it was indeed a SNAKE! It was suspended underneath two inches of ice and still alive!!! They broke the ice and tried to free the snake only to discover that its tail was encased in ice and it was stuck unable to move. So they continued to carefully chop ice until they managed to free the entire snake. They brought it inside so that it could gradually warm up. It began moving around. He was concerned about releasing it after everything it had been through only to die of exposure. So I assured him that if he brought it to me I would keep it until April. At 10:30 this morning he brought into my office. I was able to identify it as a Northern Watersnake, which is a very common and feisty snake in Missouri.

I was completely fascinated by this situation. A snake out in winter? A snake buried in ice and still alive? How long had it been there? How did it end up in this predicament? Will it ultimately succumb to death from the stress?

We figured the snake had to be under that ice for a minimum of 24 hours given the recent weather conditions. We've had unusual weather this winter, certainly not the typical cold that we generally have. Several days have topped out near 60 degrees and many more days in the 50's. Although the night time lows have been in the 20's or 30's for over a week now. How could this snake survive such extreme conditions? It must be a tribute to the hardiness of this species, or maybe this is a fluke.

I brought the snake home to photograph it. I took it out of the cloth bag I carried it home in and proceeded to show it to my daughter (who is used to me bringing all sorts of things home and shoving them in her face to see). The snake suddenly perked up and shot out of my hand onto the kitchen table and straight into my daughters lap! She shrieked, the snake hit the floor. I grabbed the snake up off the floor only to have it sling musk all over me and my daughter. She shrieked "MOM!!!!" and ran into the other room. I just shrugged and said "sorry." She started gagging at the smell, which made me laugh as I put the snake safely back into the cloth bag.
Never a dull moment around here!

If the snakes actions are anything to go by it should be fine and survive to be released. I am curious though if anyone else has found a snake in a similar situation.

Tuesday, January 24, 2012

Monday's Specie in Peril---San Francisco Garter Snake

This strikingly beautiful snake is the San Francisco Garter Snake (Thamnphis sirtalis tetrataenia) and is considered one of the most critically endangered animals in North America. They occur in a very small range in the San Francisco Peninsula and south near the San Francisco-San Mateo county border and along the eastern and western base of the Santa Cruz Mountains. In 1966 they became the first animal to be listed with the government enacted Federal Endangered Species Act. Several years later in 1971 they were listed on the California endangered species list.

Because of their limited range and low litter size they fell victim to population crashes due to pollution, habitat destruction by land development, agriculture, commercial building, residential building and recreational pursuits. Another factor that has hurt this species population is its preferred prey item. The Red-Legged Frog is the primary diet of these garter snakes and they are also listed as threatened or endangered in nearly all their range. So we have a case of an endangered species, feeding on an endangered species. They will also feed on other amphibians such as the non-native (To California) bullfrog....however, they are unable to swallow a fully grown bullfrog instead they may find themselves on the menu as bullfrogs often feed on small snakes. Unlike most animals this species of snake is even able to feed on the Pacific newt which is fatally toxic to other predators which may try to consume it. These snakes will also consume small birds, reptiles, slugs, earthworms, leeches and fish.
We also have the pet trade to thank for the descrease in numbers for this species. Many collectors in Europe have these snakes in their personal collections and there is even some speculation that there may be more in captivity in Europe than exist in their native range!

Mating occurs either in the fall or spring. If females are bred in autumn they will retain the males sperm until the following spring. Live young are born in the autumn. The juveniles are born looking nearly identical to the adults and measure up to 9 inches in length. The adults are capable of reaching lengths up to 51 inches. Like most garter snakes this species is most active during daylight hours where it may be seen on roadways basking. Please give them the right of way by slowing down and driving around them. There are an estimated 1,000-2,000 individual snakes in the wild.

They are a semi-aquatic species and can be found near ponds, marshes and sloughs. They are a secretive snake and quick to flee if approached. In the late summer or early fall they may head to higher elevations in search of prey items and hibernation locations. They will often utilize rodent burrows for hiding places and hibernation dens. 

Much research still needs to be done on this species as much of its habitat occurs on privately owned land and has not been fully studied. Anyone coming across this snake in its native home should leave it be. If you see one on the road, instead of running over it, drive around it. It would be a sad day indeed to lose such a gorgeous snake to extinction. 

Friday, January 20, 2012

There is breaking news about the Claxton Rattlesnake Roundup in Georgia. This is what Jim Ries of One More Generation and Rise Against Rattlesnake Roundups had to say:

"Beth Grant, Bill Matturro from PALS, Collette L. Adkins Giese from the Center for Biological Diversity, Dr. Lock from the ATL Zoo, Dr. Michael Black from GSU and the OMG Team just got off a conference call with many other folks about the Rattlesnake Round-ups, and we learned truly amazing news!

The Claxton group has decided to convert their March event to the Claxton Rattlesnake and Wildlife Festival without a round-up!!!!!! The folks at P.A.L.S, especially Bill, Carter and Olivia from One More Generation, as well as DNR staff all deserve big kudos for bringing the issues to the Claxton group's attention and helping them come to the conclusion to change their events!

We all need to support them in this for their own sake and also to serve as an example for Whigham. More ideas on this to follow, but to begin with, we all echo the Georgia DNR Chief, Non-game Conservation Section Wildlife Resources Division Georgia DNR, who writes:

I encourage you to contact Bruce Purcell and offer support for his work to change the event to the "Claxton Rattlesnake and Wildlife Festival".

Bruce Purcell 912-282-4052

Evans County Wildlife Club
P.O. Box 292
Claxton, Georgia 30417"

Deciding to confirm this, I called Bruce Purcell at the number listed. After a lengthy phone conversation Bruce confirmed that all of this is true. It should be noted that the festival did not have to change but it wanted to and they are hoping for a successful reformation. The last part of this message cannot be emphasized enough: call him, write to him and tell him that you fully support his decision! He is getting some negative feedback and it is the utmost importance that we counter this.

I will also encourage people to visit this reformed festival if at all possible, this may be a victory for rattlesnakes but we cannot abandon the battlefield at such a critical hour! Roundup proponents will push back and it is our duty to stop them in their tracks.

Wednesday, January 18, 2012

Legendary Kansas herpetologist Joe Collins dies

By Stan Finger The Wichita Eagle

Joe Collins studies a 64-inch Western rat snake during the Kansas Herpetoligical Society's Spring 2003 Field Trip at the Wilson State Fishing Lake and Wildlife Area. During the field trip, at least 35 species of snakes and reptiles were gathered. That is nearly a third of the 98 species found in Kansas.

Joe Collins studies a 64-inch Western rat snake during the Kansas Herpetoligical Society's Spring 2003 Field Trip at the Wilson State Fishing Lake and Wildlife Area. During the field trip, at least 35 species of snakes and reptiles were gathered. That is nearly a third of the 98 species found in Kansas.
As far as Joe Collins was concerned, snakes have had a bad rap ever since the Garden of Eden.
Mr. Collins’ passion for herpetology inspired generations of students and outdoors enthusiasts.
“For 60 years, I have been obsessed with herpetology,” Mr. Collins said in a video shot by Dan Krull. “I make no apologies for it ... the thrill of discovery just can’t be beat.”
Mr. Collins, who founded the Center for North American Herpetology and was a former instructor at the University of Kansas, died Saturday of a heart attack in Florida. He was 72.

Mr. Collins and his wife, Suzanne, were on their annual five-week trip to document wildlife – such as snakes, turtles and alligators – when he was stricken.“He was a great mentor to students of all ages, from the very smallest student who might come to him with a tiny little snake to Ph.D. students working on their dissertation,” Suzanne Collins said. As news of his death spread, many of those who considered Mr. Collins a mentor offered tributes to him on Facebook.

“I remember all these excited kids (including me) running up to Joe with pillow cases full of snakes and lizards, and Joe being equally excited to educate them about what they found,” Mike Zerwekh of San Diego wrote in a forum dedicated to Mr. Collins. “Since then, I’ve made a lot of friends and had some great adventures finding the animals I love. If it wasn’t for Joe, I’m not sure any of that would have happened. He was a true inspiration ... ”

Snakes have a reputation for being evil, which Mr. Collins blamed on the biblical story. But he loved telling audiences how beneficial snakes are to the environment, Suzanne Collins said. They eat enormous numbers of insects and disease-carrying, crop-eating rodents.“He considered reptiles and amphibians to be his animals,” she said. “He was so passionate and dedicated his life to it.”Travis W. Taggart, curator of herpetology at the Sternberg Museum of Natural History at Fort Hays State University, said Mr. Collins’ enthusiasm was infectious.“He really had an eye for people who were wide-eyed about herpetology,” Taggart said. “He was really good at nurturing it and feeding those interests.”

Joe Collins studies a lizard in his lab in the basement of his Lawrence, Kan., home. The lizard, preserved in alcohol, was found in Topeka
Joe Collins studies a lizard in his lab in the basement of his Lawrence, Kan., home.
The lizard, preserved in alcohol, was found in Topeka

Most people have hobbies, Taggart said, but Mr. Collins didn’t. He was focused at all times on herpetology.
“He woke up thinking about it, and he went to bed thinking about it,” Taggart said.
While Mr. Collins often said he disliked writing, he wrote numerous books. By his own count, he wrote more books about Kansas wildlife than anyone in the history of the state. That’s because he knew books were a vital way to convey information, said Bob Gress, director of the Great Plains Nature Center in Wichita.
Perhaps Mr. Collins’ proudest writing accomplishment was serving as co-author for a Peterson Field Guide: “Reptiles and Amphibians of Eastern and Central North America.” Snake enthusiasts consider it the bible of herpetology.

“He was one of those special people that could bridge the academia world with the hobbyist,” Gress said. “He brought interest to the masses.”Taggart said he would talk to Mr. Collins frequently – about every other day – about one thing or another.“I’ll miss those conversations,” he said. “You tend to take it for granted. There was a whole lot of wisdom there to tap into.“It’s a little scary going forward not having that insight and that push.”Taggart said his herpetology decisions will be guided by a simple question going forward: What would Joe have done if he were still here? Mr. Collins’ legacy will continue to blossom in the years ahead, he said.“He’s touched so many people, it can’t help but go on,” Taggart said. “He had so many great ideas and got so many things started.”

A memorial service will be held in Lawrence, Suzanne Collins said, but details haven’t been finalized.

Monday, January 16, 2012

Monday's Species in Peril

Since this blog was created to provide education to our readers about the plight of Herps. throughout the World, I thought it only appropriate that we dedicate one day a week to an Amphibian or Reptile that is classified as threatened, endangered or extinct in the wild. Unfortunately there will be plenty to choose from. Many of us do not think of Herps. when we think of endangered animals, instead our thoughts turn to animals such as Bald Eagles, Manatees or Tigers. Each of these animals are facing challenges to be sure, but because of their over all human appeal they have a dedicated following of people trying to help their plight. Herps. on the other hand are often overlooked by the average person. I cannot tell you how many times I've heard people make comments like "the only good snake is a dead snake" or another "I wish all snakes were dead." What these people do not realize or seem to care about, is that these snakes that they fear or hate so much are an important component in their varied habitats. Snakes are excellent at controlling over population of rodents, and they are also an important food source for many predators. Frogs are often over looked as anything more than just a cute little inhabitant of pond and lakes. The truth is, frogs are an indicator of the over all health of an ecosystem. Scientist often rely on frogs to help them solve any number of environmental mystery's concerning pollution and other contaminants. We need to change our attitudes about these often misunderstood and overlooked creatures. We should respect their role in the environment and do our best to understand and tolerate their presence.

Today's first featured species in peril is the Kihansi Spray Toad (Nectophrynoides asperginis) which was found and first described in 1998 and subsequently declared extinct 14 short years later in 2012.

This tiny toad has been declared extinct in the wild on the IUCN Red List of Threatened Species. This species had a very limited and specific habitat in the spray runoff and nearby wetland of  Kihansi Falls in the Kihansi Gorge in the Udzungwa Mountains of eastern Tanzania. With approximately a 5 acre area to inhabit it was very restricted and became victim to habitat loss and destruction. This often happens to animals with very specified habitat needs. They do not have the ability to readily adapt to a new or altered environment and often become critically endangered or in the case of this little toad they become a thing of the past in the wild. At one point in time this toad had as many as 17,000-20,000 individuals in its 5 acre range. These toads are truly small at only 3/4 of an inch as adults. This species has no tadpole stage, instead the female gives birth to 3-15 tiny toadlets. They will gain the adult coloring as they age, but otherwise look almost identical to their adult counterparts.

Animals with reduced habitats often fall victim to parasites, diseases or other health related issues. If these diseases are brought into a given environment, a species that is as fragile as a toad would stand very little chance of having adequate resources to fight it. This toad was exposed to a fungal disease called chytridiomycosis which is known to affect at least 30% of the amphibian species worldwide. In the wild this fungus cannot be controlled and often wipes out a 100% of a frog or toad population in a given area. Then in the year 2000 a dam was built on the Kihansi river which reduced water flow by 90% to the gorge where this toad is native. These frogs rely on the spray given off by the water falls of this area, with the building of the dam and the resulting  flow restriction of the river, the falls no longer create significant spray. This affects the vegetation around the falls which in turn affects the toad. This little toad was dealt a double whammy with the loss of habitat and a fungal disease it had no ability to fight off. The tiny 5 acre area that was home to this toad was so severely altered that the toad gave way to the challenges of a newly formed habitat. It could no longer survive in the wild. The only hope this toad has as a species is in captive breeding programs that are under way at the Toledo and New York Bronx Zoos. Educational programs are in place and the people of Tanzania are being taught proper husbandry techniques in order to rebuild a sustainable habitat for these toads with the hope of being able to begin releasing them back to their natural habitat.

Friday, January 13, 2012

Fun Fact Friday

I thought it might be fun to feature a fun fact or bit of trivia about the wonderful world of Amphibians and Reptiles. So each Friday is now Fun Fact Friday.

Your first fun fact is...................

The male Mallorcan Midwife Toad (Alytes muletensis) Carries its eggs wrapped around its hind legs. Once in awhile he will hop in the water to wet them.

If you would like to learn more about these interesting frogs visit Mallorcan Midwife Toady

Saturday, January 7, 2012

Round em' UP By: David Steen Ph. D.

This column ran in the papers about a month ago...

It’s that time of year again, when people congregate in a few scattered festivals across the southeastern United States to celebrate the Eastern Diamondback Rattlesnake. Well, I guess celebrate isn’t the right word, since the snakes are eventually slaughtered. I certainly understand why people wouldn’t want rattlesnakes in their yard, but I’m not quite sure I understand the appeal in capturing snakes in the wild, far from human establishment, only to kill them. I remain unconvinced by claims that these rattlesnakes serve some greater purpose, with their venom being important for medical research. Why wouldn’t captive rattlesnakes serve the same purpose? And what companies are buying venom for research from a weekend festival in small town USA?

I concede rattlesnakes aren’t particularly loved by many and catching them for roundups isn’t illegal; unless of course, while catching rattlesnakes you deal irreparable harm to other protected creatures or their habitats. In the past, pouring gasoline down gopher tortoise burrows was a popular method of catching rattlesnakes. Groggy from the fumes, snakes leave the burrow and are easily bagged. However, any tortoises hiding within the burrow stay underground and may suffer severe lung damage. You probably know tortoises are increasingly rare, being federally protected in the western portion of their range and a candidate for listing everywhere else.

Publically, rattlesnake hunters will never acknowledge they continue to catch rattlesnakes by pouring gasoline down gopher tortoise burrows, an illegal practice. Although, an individual associated with one of the remaining roundups admitted to me the practice still occurs. But, I admit anonymous sources don’t carry a lot of weight. That’s why I recently read with interest about a few people cited for destroying wildlife habitat in Silver Lake Wildlife Management Area, in Georgia, on January 28th. These individuals admitted they were catching rattlesnakes by pouring gasoline down tortoise burrows. We can only guess as to why they were motivated to capture these snakes or what they had in mind for them. But, in any case, this should be clear and unequivocal evidence that people are still pouring gasoline down tortoise burrows in areas where we hunt, fish, and recreate.

So here we are, time for the annual rattlesnake “festivals” again. If you plan to attend, feel free, but go with full knowledge of what you’re supporting with your money. All remaining roundups in the southeast have been approached by multiple organizations and individuals eager to help them transition from events that sponsor rattlesnake capture and killing to more wildlife friendly events. Because they’re important to local communities, nobody wants these festivals shut down, but there are compromises that will help ensure the integrity of our natural habitats and wildlife. Perhaps you’ve attended Fitzgerald Georgia’s annual festival (a former roundup) or San Antonio Florida’s rattlesnake celebration, where thousands of people attend each year to see captive snakes displayed. Whether you hate rattlesnakes or love them, I think it’s time we all agree that wanton destruction of wildlife and their habitats is not something we should support.

David A. Steen received his Ph.D. from Auburn University, his B.S. from the State University of New York-College of Environmental Science and Forestry, and his B.S. from the University of New Hampshire. He researches the ecology and conservation biology of wildlife and blogs about his work at His copyrighted work appears here under a Creative Commons license.

Thursday, January 5, 2012

Great Plains Toad

This adorable little amphibian is a Great Plains Toad (Bufo cognatus), they are native to Missouri but only occur in portions of the Missouri River flood plain. While Joey and I were hiking at Sunbridge Hills Conservation Area in the Bluffs of the Missouri River just on the outskirts of St. Joseph last summer I found this toad hopping around in some tall grasses. I could tell right away that his coloring and markings were different than the toads I see at home. I captured him and brought him home for a positive ID. Imagine my surprise to learn I'd found a toad that is only found in a scant few counties in Missouri. These are a medium sized species measuring up to 4 inches with the state record being 4 inches. This one measures just under 2 inches. Their coloring is highly variable and can be gray, brown, dark green, green or yellow. This one was a muted olive green color with some gray areas. Males are smaller than females, and I suspect this is a female. In Missouri this particular species has not been studied so little is known about its natural history. In other states of occurrence it is known to favor mixed grasslands and short grass prairies. It is reported to avoid forested areas, which might be refuted in Missouri as this one was definitely caught in a grassy knoll next to a forested area. Since the known habitat preference in Missouri is the Missouri River flood plain, and there are huge stands of forested areas all along the flood plain, perhaps in Missouri its habitat preference varies compared to other parts of its range.

The hopping pattern of this toad is completely different from the more common Eastern American Toad, it is much faster with longer leaps. It took quite an effort to capture this one. There is nothing awkward or slow about this species. They seem to be a little more nervous around people and prone to flee quickly..

They are excellent at burrowing into the ground and frequently do so during dry or cold spells, which in Missouri can be a large portion of the year. With the impending flood of the Missouri River many animals are being pushed to higher ground and that may be the case with this particular specimen as it was found in the bluffs of the Missouri River. In St. Joseph the Missouri River flood stage is 17 feet and we are currently at 23 feet and rising. Up north in Minnesota because of excessive rainfall their reservoir is full and they are being forced to release water, which is causing catastrophic flooding of farm ground, and low lying areas south of the dam. It is guesstimated to reach 33 feet in St. Joseph before it is over, which is a full foot higher than the record breaking flood of 1993 where 1,000's of people were displaced from their homes and billions of dollars in damages occurred, not to mention the injuries and loss to life.

The great plains toad breeds in late spring or early summer when the males begin calling. Their call has been described as sounding very much like an explosive jackhammer-like metallic trill that is deafening when heard up close. These toad breed right after heavy rainfall, which could explain why I found her out in the open, the night before we had a huge rainfall, and it probably put her in the mood for love. Females can lay large amounts of eggs, in fact specimens in Oklahoma were found to lay as many as 45,000 eggs. Males stay near the female to capture the eggs between his legs in a "basket" of sorts. Presumably this is to make sure his sperm is the one who fertilized the eggs. The eggs are then laid in long strands in shallow bodies of water. Many females may chose the same watering hole for egg laying. It takes a week for the eggs to hatch and up to a month for them to reach adult size.

The main enemy of this toad is the plains garter snake. Garter snakes are noted for eating toads and frogs. I even managed to capture a picture a few years ago of a garter snakes trying to eat an Eastern American Toad in my backyard(pictured below). These snakes hang around our goldfish pond waiting for an opportunity to capture and eat the frogs and toads.

Getting outside and exploring is sure to bring with it many cool discoveries. This toad was one of many great finds of a warm summer night.

Sunday, January 1, 2012

Western Massasauga Rattlesnake

Here is a snake hovering on the brink of extinction in Missouri as well as throughout most of its range. The Western Massasauga (pronounced mass-a-saw'-ga) Rattlesnake is one of the smallest rattlesnakes found in Missouri wetlands and marshes. Because these lands are greatly reduced due primarily to agriculture, it is becoming increasingly more difficult for these snakes to carve out a niche for themselves. Squaw Creek NWR has a fairly healthy population of these snakes in large part because the land is federally owned and the snakes are protected there. Ongoing studies help to determine population density and over all health of the snakes. The one pictured here is a captive snake used as an educational animal to help promote the importance of all creatures within their given habitat. Snakes are especially important in rodent control and as a vital part of the food chain and should be left alone. They are also indicators of the health of their environment. 

In the Chippewa language Massasauga translates into "great river mouth" which describes the lands where they are found. Like all Missouri venomous snakes they are "pit-vipers" , meaning they have an extra sensory organ in the form of pits located between the eyes and the nostrils. These pits are heat sensing organs that help them locate prey. They also have excellent eye sight and a great sense of smell. All of these senses combined make for a formidable predator. They commonly prey on mice, frogs, insects. Juveniles are fond of other serpents with Midland Brown Snakes making up the bulk of their diet. These snakes are also an important part of the food chain and sometimes fall victim to eagles, herons, raccoons, foxes, and hawks. Not to mention the occasional motorist who would rather kill snakes as to look at them. This near-sighted viewpoint of snakes is what has led to the near extinction of many species. Humans should try to exercise tolerance for these misunderstood creatures and recognize their importance in the over all health of a given habitat.

These are a slow moving snakes that rarely strike unless being provoked or handled. Their venom is less toxic than that of most venomous snakes, but should still be considered dangerous. If bitten; immediate medical attention should be sought.  During the spring they will be found in lowlands near marshes and wetlands. In the hotter summer months they are found in higher ground near grasslands, farmland and open fields. Like all snakes they are often found sunning themselves on rocks, and roadways. Massasauga rattlesnakes reach lengths up to thirty inches. Their ground color is gray or tan with numerous darker spots, there are even melanistic black varieties found occasionally.

Massasaugas are ovoviviparous (eggs develop in the body of the parent and hatch within or immediately after being expelled). The female produces large, yolk-filled eggs which are retained within her reproductive tract for a considerable period of development. The developing embryo receives no nourishment from the female, only from the yolk. Eggs of the Massasauga hatch inside the female and the young are born “alive.” A female snake that retains eggs in her body can bask in the sun, thus raising the temperature of the eggs and speeding their development, resulting in a variable gestation period of two to four months. The average litter size is 8 with anywhere from 3 to 12 being possible.

After birth, the young are on their own—no maternal care is known in snakes. As is the case for all cold-blooded vertebrates, the growth of the young is heavily dependent upon the amount of food available.