Common Animal Questions and Answers

Common Animal Questions and Answers The animal kingdom is fascinating and often inspires a number of questions from both the young and old. Why do zebras have stripes? How do bats locate prey? Why do some animals glow in the dark? Find answers to these and other intriguing questions about animals. Why Do Some Tigers Have White Coats? Researchers from Chinas Peking University have discovered that white tigers owe their unique coloration to a gene mutation in the pigment gene SLC45A2. This gene inhibits the production of red and yellow pigments in white tigers but does not appear to alter black. Like orange Bengal tigers, white tigers have distinctive black stripes. The SLC45A2 gene has also been associated with light coloration in modern Europeans and in animals such as fish, horses, and chickens. The researchers advocate for the possible reintroduction of white tigers into the wild. Current white tiger populations only exist in captivity as wild populations were hunted out in the 1950s. Do Reindeer Really Have Red Noses? A study published in the BMJ-British Medical Journal reveals why reindeer have red noses. Their noses are abundantly supplied with red blood cells through the nasal microcirculation. Microcirculation is the flow of blood through tiny blood vessels. Reindeer noses have a high density of blood vessels that supply a high concentration of red blood cells to the area. This helps to increase oxygen to the nose and to control inflammation and regulate temperature. The researchers used infrared thermal imaging to visualize the reindeers red nose. Why Do Some Animals Glow In the Dark? Some animals can emit light naturally due to a chemical reaction in their cells. These animals are called bioluminescent organisms. Some animals glow in the dark to attract mates, to communicate with other organisms of the same species, to lure prey, or to expose and distract predators. Bioluminescence occurs in invertebrates such as insects, insect larvae, worms, spiders, jellyfish, dragonfish, and squid. How Do Bats Use Sound to Locate Prey? Bats use echolocation and a process called active listening to locate prey, typically insects. This is particularly helpful in clustered environments where sound can bounce off of trees and leaves making it more difficult to locate prey. In active listening, bats adjust their vocal cries emitting sounds of variable pitch, length, and repetition rate. They can then determine details about their environment from the returning sounds. An echo with a sliding pitch indicates a moving object. Intensity flickers indicate a fluttering wing. Time delays between cry and echo indicate distance. Once its prey has been identified, the bat emits cries of increasing frequency and decreasing duration to pinpoint its preys location. Finally, the bat emits what is known as the final buzz (rapid succession of cries) before capturing its prey. Why Do Some Animals Play Dead? Playing dead is an adaptive behavior used by a number of animals including mammals, insects, and reptiles.  This behavior, also called thanatosis, is most often employed as a defense against predators, a means to catch prey, and as a way of avoiding sexual cannibalism during the mating process. Are Sharks Color Blind? Studies on shark vision suggest that these animals may be completely color blind. Using a technique called microspectrophotometry, researchers were able to identify cone visual pigments in shark retinas. Of the 17 shark species studied, all had rod cells but only seven had cone cells. Of the shark species that had cone cells, only a single cone type was observed. Rod and cone cells are the two main types of light sensitive cells in the retina. While rod cells can not distinguish colors, cone cells are capable of color perception. However, only eyes with different spectral types of cone cells can distinguish different colors. Since sharks appear to have only a single cone type, it is believed that they are totally color blind. Marine mammals such as whales and dolphins also have only a single cone type. Why Do Zebras Have Stripes? Researchers have developed an interesting theory as to why zebras have stripes. As reported in the Journal of Experimental Biology, zebras stripes help to ward off biting insects such as horseflies. Also known as tabanids, horseflies use horizontally polarized light to direct them toward the water for laying eggs and to locate animals. The researchers state that horseflies are more attracted to horses with dark hides than those with white hides. They concluded that the development of white stripes prior to birth helps to make zebras less attractive to biting insects. The study indicated that the polarization patterns of reflected light from zebra hides were consistent with stripe patterns that were least attractive to horseflies in tests. Can Female Snakes Reproduce Without Males? Some snakes are capable of reproducing asexually by a process called parthenogenesis. This phenomenon has been obeserved in boa constrictors as well as in other animals including some species of shark, fish, and amphibians. In parthenogenesis, an unfertilized egg develops into a distinct individual. These babies are genetically identical to their mothers. Why Dont Octopuses Get Tangled in Their Tentacles? Hebrew University of Jerusalem researchers have made an interesting discovery that helps answer the question of why an octopus doesnt get tangled up in its tentacles. Unlike in the human brain,  the octopus brain does not map out the coordinates of its appendages. As a result, octopuses dont know where their arms are exactly. To prevent the octopuss arms from grabbing the octopus, its suckers will not attach to the octopus itself. The researchers state that an octopus produces a chemical in its skin that temporarily prevents the suckers from grabbing. It was also discovered that an octopus can override this mechanism when necessary as evidenced by its ability to grab an amputated octopus arm. Sources: Cell Press. White tiger mystery solved: Coat color produced by single change in pigment gene. ScienceDaily. ScienceDaily, 23 May 2013. (www.sciencedaily.com/releases/2013/05/130523143342.htm).BMJ-British Medical Journal. Experts discover why Rudolphs nose is red. ScienceDaily. ScienceDaily, 17 December 2012. (www.sciencedaily.com/releases/2012/12/121217190634.htm).Chanut F (2006) The Sound of Dinner. PLoS Biol 4(4): e107. doi:10.1371/journal.pbio.0040107.Springer ScienceBusiness Media. Are sharks color blind?. ScienceDaily. ScienceDaily, 19 January 2011. (www.sciencedaily.com/releases/2011/01/110118092224.htm).The Journal of Experimental Biology. How the zebra got its stripes. ScienceDaily. ScienceDaily, 9 February 2012. (www.sciencedaily.com/releases/2012/02/120209101730.htm).Cell Press. How octopuses dont tie themselves in knots. ScienceDaily. ScienceDaily, 15 May 2014. (www.sciencedaily.com/releases/2014/05/140515123254.htm).

The Irish Elk, the Worlds Biggest Deer

The Irish Elk, the World's Biggest Deer Although Megaloceros is commonly known as the Irish Elk, its important to understand that this genus comprised nine separate species, only one of which (Megaloceros giganteus) reached true elk-like proportions. Also, the name Irish Elk is something of a double misnomer. First, Megaloceros had more in common with modern deer than American or European Elks, and, second, it didnt live exclusively in Ireland, enjoying a distribution across the expanse of Pleistocene Europe. (Other, smaller Megaloceros species ranged as far afield as China and Japan.)    The Irish Elk, M. giganteus, was far and away the largest deer that ever lived, measuring about eight feet long from head to tail and weighing in the neighborhood of 500 to 1,500 pounds. What really set this megafauna mammal apart from its fellow ungulates, though, were its enormous, ramifying, ornate antlers, which spanned almost 12 feet from tip to tip and weighed just short of 100 pounds. As with all such structures in the animal kingdom, these antlers were strictly a sexually selected characteristic; males with more ornate appendages were more successful in intra-herd combat, and thus more attractive to females during mating season. Why didnt these top-heavy antlers cause Irish Elk males to tip over? Presumably, they also had exceptionally strong necks, not to mention a finely tuned sense of balance. The Extinction of the Irish Elk Why did the Irish Elk go extinct shortly after the last Ice Age, on the cusp of the modern era, 10,000 years ago? Well, this may have been an object lesson in sexual selection run amok: Its possible that dominant Irish Elk males were so successful and so long-lived that they crowded other, less-well-endowed males out of the gene pool, the result being excessive inbreeding. An overly inbred Irish Elk population would be unusually susceptible to disease or environmental changesay, if an accustomed source of food disappearedand prone to sudden extinction. By the same token, if early human hunters targeted alpha males (perhaps wishing to use their horns as ornaments or magic totems), that, too, would have had a disastrous effect on the Irish Elks prospects for survival. Because it went extinct so recently, the Irish Elk is a candidate species for de-extinction. What this would mean, in practice, is harvesting remnants of Megaloceros DNA from preserved soft tissues, comparing these with the gene sequences of still-extant relatives (perhaps the much, much smaller Fallow Deer or Red Deer), and then breeding the Irish Elk back into existence via a combination of gene manipulation, in-vitro fertilization, and surrogate pregnancy. It all sounds easy when you read it, but each of these steps poses significant technical challengesso you shouldnt expect to see an Irish Elk at your local zoo anytime soon! Name: Irish Elk; also known as  Megaloceros giganteus  (Greek for giant horn); pronounced meg-ah-LAH-seh-russ Habitat: Plains of Eurasia Historical Epoch: Pleistocene-Modern (two million-10,000 years ago) Size and Weight: Up to eight feet long and 1,500 pounds Diet: Plants Distinguishing Characteristics: Large size; large, ornate horns on head