Northern water shrew
The American water shrew (Sorex palustris) is a mole-like mammal found throughout North America. This tiny animal lives in semi-aquatic habitats and is known for being the smallest mammalian diver.
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NocturnalNocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal",...
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CarnivoreA carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of a...
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InsectivoresAn insectivore is a carnivorous plant or animal that eats insects. An alternative term is entomophage, which also refers to the human practice of e...
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NatatorialNatatorial animals are those adapted for swimming. Some fish use their pectoral fins as the primary means of locomotion, sometimes termed labriform...
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ViviparousAmong animals, viviparity is the development of the embryo inside the body of the parent. The term 'viviparity' and its adjective form 'viviparous'...
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SemiaquaticSemiaquatic animals are those that are primarily or partly terrestrial but that spend a large amount of time swimming or otherwise occupied in wate...
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AltricialAltricial animals are those species whose newly hatched or born young are relatively immobile. They lack hair or down, are not able to obtain food ...
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SolitaryNo
Not a migrantAnimals that do not make seasonal movements and stay in their native home ranges all year round are called not migrants or residents.
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starts withThe American water shrew has a black and brown pelage which varies in shade depending on the season. When underwater, the animal appears to have a silver veneer on account of its water-repellent fur trapping air bubbles. The snout features vibrissae which in the case of water shrews are specialized for aquatic hunting. Like other small mammals who spend part of their time in the water, American water shrews have short hairs covering their hind limbs to bolster each paddle with increased surface area, an adaptation not dissimilar to flippers. The males of this species are generally larger and heavier than the females.
American water shrews occur in the central and eastern regions of Canada and the northern United States, as well as a small isolated section of the Appalachian mountain range. They are also found in the western United States and Canada. American water shrews prefer to live along streams of higher inclines, springs, mud flats, marshes, ponds, bogs, and even beaver dens.
American water shrews are solitary and can be active during the day or night. They are rarely found far from water since their diet consists almost entirely of small aquatic invertebrates and fishes. They also hunt land prey depending on the ease of the attack but mainly target aquatic prey by diving from rocks or elevated banks of streams. American water shrews usually hunt at night and don't use eyesight while locating their prey underwater. According to Kenneth C. Catania's research, nocturnally diving shrews manage to locate their prey in the obscured stream by detecting movement along their whiskers or by “underwater sniffing”; this is a strategy in which they exhale air bubbles onto a perceived target and then re-inhale their own air bubbles to confirm the presence of prey.
American water shrews are carnivores (insectivores). They feed mainly on aquatic insects but can also eat other invertebrates, small fish, and amphibians.
American water shrews breed between February and August. They nest in underground burrows located near water. Females usually have a three-week gestation period, and offspring are born in the spring and summer. They usually produce 2 to 3 litters during that time. These litters can contain 3 to 10 offspring.
American water shrews are threatened by the loss of their aquatic and terrestrial habitats. They also suffer from the use of pesticides when eating invertebrates. Isolated populations that live in the mountains suffer from human activities and climate changes.
The IUCN Red List and other sources don’t provide the number of the American water shrew total population size. Currently, this species is classified as Least Concern (LC) on the IUCN Red List, and its numbers today are stable.
