Wednesday, March 30, 2016

Rare North American Frog Species


North America seems to be a haven for frogs and toads. There are more than a hundred species in North America and not a single state or country on the continent is without one or more species. Frogs are abundant in North America. However, there are some species of frogs on the continent that are rare and sometimes elusive. Habitat tends to be the cause of rarity for all of the following frog species. For some it is habitat loss that is causing a problem with the population. Others just have a naturally small range. Either way, the effect is the same. These frogs are very difficult to find.

Rare North American Frogs: Florida Bog Frog

The Florida Bog Frog can only be found in a very small portion in the Midwestern area of Florida’s panhandle. In that area, they can only be found in the drainages of the East Bay River, the Titi Creek and the Lower Yellow River. They are not considered endangered, however, their very limited range makes them very vulnerable to habitat destruction or alteration.

Florida Bog Frogs are green or murky green in color. They may have darker greenish spots on their backs and/or light yellowish-green spots on their sides. They have very little webbing on their rear feet. They grow to be between 1-3/8 inches and 1-15/16 inches in length.

As is the case with most frog species, Florida Bog Frogs are much easier to find during the mating season, when the males are emitting their mating calls. This happens between April and August, sometimes as late as September.

Rare North American Frogs: Pine Barrens Treefrog

The Pine Barrens Treefrog can be found in New Jersey, the far western Florida panhandle, a very small portion of southern Alabama, and small portions of both North and South Carolina. They can be found in boggy areas where they breed in the spring and summer. Males are often more active in their mating calls after it rains.

Pine Barrens Treefrogs are medium green with a white and brown stripe from their snout all the way down their sides. The stripe may be speckled yellow near the frog’s joints. They grow to be between 1-1/8 inches and 2 inches in length.

Rare North American Frogs: Relict Leopard Frog

Relict Leopard Frogs are only found in a very small area in southeastern Nevada into northwestern Arizona. Their population has declined and their range has decreased in size due to invasive species and habitat changes.

Relict Leopard Tree Frogs are light brown to dark greenish-black in color. They often have darker markings all over. They may grow to be between 1-3/4 inches and 3-1/2 inches in length. They breed between February and April and again in November. However, their calls are very difficult to hear because they are often made underwater.

With the right habitat conservation efforts and/or captive breeding and release programs, not only can we ensure that these rare frog species will survive, but we may also be able to increase their numbers. Some of these frog species are already receiving the help they need. Others are not in dire need of any assistance, but habitat conservation should always be kept in mind.

Source

Elliott, Lang & Gerhardt, Carl & Davidson, Carlos, The Frogs and Toads of North America Houghton Mifflin Harcourt, 2009 p. 228-229, 292-293, 204-205, 52-55

Monday, March 14, 2016

Ways That Snakes Defend Themselves

Eastern Diamondback Rattlesnake
Snakes are highly efficient predators. They are stealthy, they are fast and some of them are even packing lethal venom. It is hard to imagine that such skilled hunters would need defense mechanisms, but obviously they do. No animal on Earth is exempt from becoming prey. Snakes may be preyed upon by predatory birds, other snakes, small mammals and more. Lucky for them, most snake species have evolved with instinctual defensive behaviors and/or physical attributes that aid in their defense. Here are just a few of the more common ways that snakes can defend themselves.

Ways That Snakes Defend Themselves: Warnings

When a member of some species of snakes is startled by something that it feels may be a threat, it may attempt to scare the creature off by giving it a warning. The most well known of these snake warnings is the rattle. Rattlesnakes will use their rattle as a way of saying “If you get close, I’m going to bite you.” This can be effective against animals that know the sound comes from a very dangerous snake. Other ways that snakes may warn potential predators are to hiss, puff themselves up so they look larger or to open their mouths wide as if to strike.

Ways That Snakes Defend Themselves: Balling

A very popular snake to keep as a pet is known as the Ball Python. This snake is thus named because of its habit of wrapping its body around its head when it is threatened. This is called balling. They are not the only snakes that do this to protect their head from damage, but they are the only species that are nicknamed for it.

Ways That Snakes Defend Themselves: Tail Loss

There are at least three species of snakes that are capable of ridding themselves of their tails. They do this when a predator has them by the tail. This way, the more important half of their body can escape to safety while their attacker munches on their tail.

Ways That Snakes Defend Themselves: Play Dead

There are several species of snakes that will pretend they are dead when confronted by a predator. Some will roll over on their back and let their mouth hang open. Others will go one step further by giving off a nasty scent that mimics the smell of decomposition. However, this isn’t very effective when they meet with a predator that doesn’t mind eating a dead snake.

Ways That Snakes Defend Themselves: Camouflage

Snakes can camouflage themselves in many ways. This is a great defense mechanism because it makes it very difficult for a predator to spot them. Some snakes can blend into their surroundings really well by hiding in leaf litter or holding very still so they look like a branch or a vine.

Ways That Snakes Defend Themselves: Venom

Now, most venomous snakes rarely resort to using their venom as a defense. They prefer to use their venom to kill prey. Nonetheless, they will not hesitate when need be. Spitting cobras (which don’t actually ‘spit’) spray their perceived threat with venom strictly as a warning. They never use their ‘venom spit’ to kill prey. Of course, a venomous snake without this ability will bite if they have to. They don’t want to, but they will, with the exception of a scant few highly aggressive venomous snake species. They do want to bite you and will if you get close enough.

So you see, snakes are not only very good at causing the rest of the animal kingdom to go on the defensive, they are actually quite good at playing defense themselves. Remember, if you see a snake displaying any of these behaviors, they are threatened by you. The best thing you can do is to leave them alone and walk away. They’ll eventually calm down and go about their business. Also, if you will be walking outdoors, know the snake species in the area, if possible. Some snakes are very territorial–not many, but some. The best defense against the smaller species of this category is high boots.

Sources


Chris Mattison, Snake, p. 26-29, DK Publishing, INC. 1999

Wednesday, March 2, 2016

Wood Frogs

Wood frog
Wood frog
Wood frogs are interesting little creatures that can be found in the northern parts of North America. They are relatively common animals, but that doesn't make them any less interesting.

Wood frogs can be found in the wooded areas, grasslands and tundra of northern North America. They can be found in, near or far from bodies of water in their habitat. Adult wood frogs tend to move away from the water during the summer months.

A fully-grown wood frog is typically around three inches long. They are brown, tan or pinkish in color with a white underbelly and may also have differing patterns of blackish stripes and spots on their bodies. All wood frogs have one black stripe on either side of their face that begins at the front of the face, goes past the eyes and to the eardrum located near the back of the animal’s head. They have two ridges, one on either side of the back. A telltale feature that a wood frog has are toes on their front legs that are not webbed as completely as that of some other frogs. Males also have enlarged thumbs. This not only makes it easy to tell what kind of frog they are, but it also aids in discovering the sex of the animal, if you should have the need to do so.

Wood frogs mate in the early months of spring. During the mating season, the male wood frogs will spend time in the water, calling out to potential mates. Once they see another frog that they are interested in mating with, they will jump onto it’s back and hold on. They do this to decipher the sex of the other frog, as they are unable to do this without feeling the frog to see if it is swollen with eggs. If a male frog jumps on another male frog, the offended frog will give a croak of warning and the offender will jump off of it.

Female wood frogs will lay more than one thousand eggs at a time. They lay the eggs into the water and the eggs are sometimes attached to pond debris or plant life. Wood frogs reproduce in a group setting, so all of the eggs wind up in the same area, they then become covered in algae, causing an “egg mat” to form on the surface of the water. The tadpoles are a brownish-black color when they hatch. They are adults within two months of hatching.

Wood frog tadpoles will eat algae when they are young and quickly graduate to insect larvae.  Adults eat insects, snails, slugs and worms. Birds of prey, raccoons and other small forest dwelling carnivores or omnivores may eat them.

The most interesting thing about wood frogs is their ability to freeze during hibernation. In the climates that these frogs dwell in, it is necessary to hibernate and in many of these areas, it is very cold during the winter. Wood frogs are able to find themselves some shelter under natural debris, rather than digging deep into mud or earth to hibernate, because they are able to freeze several times during hibernation and then thaw out in the spring. For more information regarding wood frog hibernation click here.

Sources

Wood Frog, retrieved 10/13/09, fcps.edu/islandcreekers/ecology/wood_frog.htm


Wood Frog, retrieved 10/13/09, enature.com/fieldguides/detail.asp?reenum=AR0033