4-13-15

For my science discovery this month, I researched tree frogs. Tree frogs are amphibians and there are over 800 species of tree frogs. Not all tree frogs live in trees, but in all tree frogs the last bone in their toes (called the terminal phalanx) is shaped like a claw. Tree frogs also have toe pads to help them climb and most tree frogs have extra skeletal structures in their toes. Tree frogs are in the hylidae family. Many of the U.S. species are green, gray, or brown. While some of them, like the squirrel tree frog (Hyla squirella) are chameleon-like in their ability to change color. Tree frogs come in many sizes an the smallest tree frogs are less than an inch long. Adult tree frogs are insectivores that eat flies, ants, crickets, beetles, moths, and other small invertebrates, but most of them start off their lives as herbivores during the tadpole stage. Tree frogs are consumed by mammals, reptiles, birds, and fish so the frogs rely on camouflage to protect themselves from predators. The lifespan of tree frogs varies among species. many tree frogs are aboreal, which means that they live in trees. But some tree frogs find habitat in lakes and ponds or amongst moist ground cover. Tree frogs are found on every continent excluding Antarctica, but they’re most diverse in the New World tropics. About 30 species live in the United States, and over 600 can be found in South America and Central America. Tree frogs breathe through their skin. Most male tree frogs attract their mates using a mating call, which changes species to species.

4-13-15

For my science discovery this month, I researched brown rats. The scientific name for brown rats is Rattus norvegicus. Brown rats can weigh up to 600g, but usually 200-300g. greyish-brown fur, prominent pointed muzzle, eyes, ears and a long (almost) naked tail that is about as long as the length of the head and body together. In captivity brown rats can live for about four to six years, but in the wild brown rats rarely live over a year. Brown rats are native to central Asia and where then introduced to the British Isles during the 1720s and were distributed through out the world on ships. Brown rats are omnivores and will eat almost anything, but mostly cereals. Foraging behavior is usually population-specific and varies by the food-source and the environment. Brown rats are not territorial and live in loose colonies with a hierarchy determined mainly by the size and the age. There are small family groups within a colony. Brown rats dig their own burrows and the entrances are commonly joined by well-used runs. Male brown rats can have ranges that average 600 m, and females 340 m. Food stores may be as small as 65 m. Predatory wise, young rats can be important food for owls, and many carnivores, including polecats, stoats and foxes, are predators to brown rats. In human dwellings brown rats observe reproduction all year round. Females may begin breeding at the age of 3-4 months old, but if food is readily available they can breed continuously, and typically have five litters per year. The litter sizes may vary and the record for brown rats' litter sizes is 22 young. Young brown rats are blind for six days when they're born and are hairless. Young brown rats are weaned at about 3 weeks of age. The common rat is considered a pest and is killed rather than conserved.