Learn more about the Etruscan Shrew by playing this science game for kids.
About the Shrew
The Etruscan shrew, one of the smallest mammals in the world, is one of its kind. Because it is so small, its muscles are very small. This has some implications. Researchers have examined the neuroanatomy of this shrew to determine its benefits and drawbacks. Its size makes it able to survive in low-level encounter rates and productivity areas. It is small in size but has an extensive range of habitats and high energy retention.
The brain of an Etruscan shrew is among the smallest mammal species. Its cerebral cortex is 400-500 um across and is cytoarchitectonically heterogeneous, with similar cortical boundaries. The presence of multiple sensory areas in the neocortical area, including the olfactory bulb, is revealed by the myelin staining and cytochrome oxide staining.
The Habitat for the Etruscan Shrew includes a range of lowland forests and grassy fields. This species is primarily found in the Mediterranean basin but can also be found in Central Asia, Central Asia, and the Arabian Peninsula. This species is likely to be territorial and solitary. It avoids open fields and seeks refuge under dense layers of organic material. This species is known to use old dry stone walls as a refuge and breeding site.
Although the brain of the Etruscan shrew may be small, its behavioral capabilities are remarkable for a creature this small. Contrary to other shrew species, which have few sensory cortical regions, Etruscans have two primary visual cortexes and one somatosensory cortex. Their neurophysiology is similar to other insectivores.
The Etruscan shrew, in addition to its human brain, has a well-organized sensory periphery. Its trigeminal nerve, which is the largest sense organ, is also highly organized. Although the brain of this tiny insectivore may not be very large, it has extensive representations of its nose and whiskers. This animal's brain also has a push-pull structure, which limits the size of its CNS.
The Etruscan shrew can respond to many auditory stimuli. However, the most effective stimulus is key ringing. High-frequency hearing is a dominant feature in this species. This can be seen by a strong preference for metallic clanging. The contralateral body surface of the shrew was mapped by using light, fast strokes with a thin, metal stick to map its sensory field. Next, the number of whiskers in each receptive area was calculated. Although most receptive areas were bilateral, the ipsilateral surface of the body was also mapped.
Some shrew species' brain sizes may show the most drastic reversible changes in mammalian central nervous system. The brain mass drops by as much as 20% in summer and then grows back between nine to sixteen percent in spring. Researchers aren't sure why, but they have found that brain structure decreases in different seasons and sexes.
The brain size of the Etruscan shrew is 400-500um. The brain is made up of a heterogeneous layer of tissue with distinct cortical boundaries and many sensory cortical regions. The S1 area, secondary somatosensory cortical cortex, and visual cortex were identified as being among the cortical areas. The brain can be divided into multiple areas by electrophysiological recordings made from Etruscan shrews.
Temperature of the body
The Etruscan shrew is distinctive because of its distinct snout and prominent whisker fan. It has both large macro vibrissae that target prey, and smaller micro vibrissae that initiate the final strike. The shrew also has six rows of whiskers on its snout. They are arranged in a variety of arcs. Because of its size and mass, it is a good candidate to be the smallest mammal. It is one of the smallest mammals on the planet, weighing in at 2.4g. Because of its small size, it is difficult to preserve body heat. Although its body heat is rapidly lost, its metabolism operates at the same temperature as a human. It is likely that its mitochondria, which are hot throughout the day, cause this. It can also breathe extremely fast: it can do so at 800 times per hour, as opposed to the 12 to 20 times per minute that humans do.
Recent research has shown that the Etruscan shrew's venom has paralytic and cardiotoxic effects. Researchers conducted physiological bioassays with frog, mealworm and common shrew saliva. The results revealed a significant difference in the response to the venom and one minute after the administration of the saliva.
The venom gland of the shrew contains enough venom to kill 200 mice. This is the equivalent of the venom from the tiger snake. This venom is used by the shrew in live hoarding. Instead of having hollow fangs, shrews have a gland which releases venom from their saliva. They inject their venom-filled saliva into the wounds of their prey when they bite it. This paralyzes prey.