The shrew: not a real mouse?! - Question meets answer | planet school скачать в хорошем качестве

The shrew: not a real mouse?! - Question meets answer | planet school

Shrews (Soricidae) look very similar to true mice (Murinae) and exhibit similar behavior; however, they are not related to them. While shrews belong to the mammalian order of insectivores, true mice are a subfamily of the mammalian order of rodents. 💬 Insectivores vs. Rodents Shrews are small, have button eyes, large ears, and busily scurry around. "Typical mouse," then, but only at first glance. In fact, the shrew—despite its name—is not a true mouse. It is not a rodent at all, but, like its relatives the mole and hedgehog, belongs to the mammalian order of insectivores. It feeds on worms and beetles, for example. True mice, on the other hand, form a subfamily of the order of rodents (Rodentia), along with rats. This largest order of mammals comprises 2,277 species, including animals as diverse as beavers and naked mole rats, prairie dogs, marmots, and dormice. They are mostly herbivores. Their habitats and appearance vary greatly. Their most important common feature is their four enlarged incisors, known as gnaws, which are located in pairs in the upper and lower jaws. The best-known and most widespread genus of true mice is the house mouse (Mus musculus). 💬 Shrew and House Mouse – Differences in Skeleton, Skull, and Dentition The shrew's skeleton is somewhat more delicate than that of the house mouse. Its skull, however, is longer; its snout tapers to a point. The biggest difference is in its dentition. The house mouse has two long and very sharp incisors in each of its upper and lower jaws. These continuously grow and are worn down as it gnaws. This ensures that they maintain their correct length and are also sharpened. The rodents' teeth are perfectly suited for hard plant foods such as roots, nuts, or grains. The shrew's teeth, on the other hand, are adapted to a predatory lifestyle. The upper and lower jaws contain many small, very sharp teeth with a very hard enamel layer. They form the teeth of an insectivore. 💬 Shrews: Successful hunters - on land and in water With their teeth, shrews can easily grasp their prey and crack the hard shells of beetles and grasshoppers. Worms and spiders are also on their menu. The water shrew, which also hunts for fly larvae or freshwater shrimp underwater, has glands under its tongue that produce a neurotoxin. With this toxin, it can paralyze its prey and thus overpower even animals larger than itself, such as frogs, newts, or small fish. 💬 Special features of the shrew - rapid metabolism Shrews have a higher metabolism than any other mammal native to our region, even relative to their body size. They move extremely fast; their hearts beat 800 to 1,000 times per minute. Because they have exclusively aerobic muscle fibers, they never get sore, despite their tireless activity. They build up virtually no fat reserves. The amount of prey they must consume daily exceeds their own weight. If they can't find food, they starve to death after just a few hours. Especially in the cold months, it is a challenge for shrews, which do not hibernate, to meet their high energy needs. Surprisingly, shrews native to northern Europe are smaller than those native to the south. This contradicts the so-called miner's rule, which states that a larger body is advantageous in colder climates. Scientific studies on forest shrews show that the animals shrink in winter to conserve energy. In the process, they lose up to 20 percent of their body weight. This change in size affects the skeleton, brain, and many other organs. The following spring, they grow back to their original size. This seasonal change in body size is also known as the Dehnels phenomenon and is of great interest for medical research—particularly the study and possible cure for osteoporosis. #QUESTIONMETANSWER #SWR #planetschule --------------- 🎬 More from Question Meets Answer: https://www.planet-schule.de/frage-tr... ⁉ WEB: https://planet-schule.de 📧 NEWSLETTER: https://www.planet-schule.de/sf/servi... ⁉️ X:   / swrbildung   🤝 SWR NETIQUETTE: https://www.swr.de/home/netiquette-10... ❗ IMPRINT: https://www.swr.de/impressum/