Giant Ottershrew

The giant otter shrew is a mammal superficially similar to an otter in appearance. It is characterized by a long, flat tail, which it uses for swimming by sideways undulation like a fish. It has a muzzle covered with bristles, and flat shielded nostrils. It has dense, soft hair, silky on the tail. It has small eyes and external ears. Its fur consists of a dense undercoat and coarse guard hairs. It possesses counter-shading with dark brown on its back and whitish or yellowish under parts. The tail is covered with a short, silky coat of fur and is compressed laterally which allow it to swim by horizontal undulations as in fishes and crocodiles. Its legs are short and lack webbing so they are not used for swimming. The hind feet have a flap of skin along the inside that allows them to be held snugly against the body when swimming. There are also two syndactylous (2nd and 3rd toes are fused) toes on the hind feet, used for grooming. On land P. velox is plantigrade. Females have two mammae on the lower abdomen for feeding young. The mass ranges from 300 grams (11 oz) to 950 grams (34 oz). Head and body length is 290 millimetres (11 in) to 350 millimetres (14 in), and reaches 535 millimetres (21.1 in) to 640 millimetres (25 in) with tail.

Giant otter shrews are native to central Africa, from the southern regions of Nigeria (central Rainforest Zone), and then eastward through Equatorial Guinea, Gabon, and the Central African Republic, Chad, the Republic of Congo, the Democratic Republic of the Congo, South Sudan to the northern regions of Angola and Zambia. There is a small population that lives between Uganda and Kenya and the preserved rainforest of Kakamega, Kenya.

The giant otter shrew builds burrows among riverbank crevices. It chooses dry leaves with which to line its nest. This is also where breeding takes place. The burrows are frequently changed. When foraging, otter shrews take frequent grooming breaks. When traveling upstream the otter shrew travels on the bank and then swims downstream. The night foraging routine is regular and predictable, and covers up to 800 meters a night. P. velox regularly visits discrete piles of feces that are sheltered and probably used to mark boundaries of territory. Giant otter shrews are solitary with one shrew occupying between 500 and 1,000 m of stream.

P. velox is a nocturnal predator, hunting primarily by touch and scent in and around calm pools. Each dive lasts only seconds. P. velox searches both within the pool and along the bank for prey using the sensitive vibrissae and odor and apparently not eyesight. It prefers areas that have cover to retreat to when it feels threatened. P. velox attacks prey using sharp bites, sometimes pinning the prey with its fore feet, and flipping crabs over to attack their weaker ventral surface. They usually avoid crabs larger than 7 cm across. The prey preference varies among individuals; some prefer crabs; others, frogs or fish. Frogs are eaten headfirst and fish are pulled apart into manageable bits. Prey is consumed on the bank. P. velox also eats insects, mollusks, and freshwater prawns. In captivity it eats 15–20 crabs per night.