Hunting and Feeding in the Spotted-Necked Otter

The information below comes from Kruuk (1995), Kwa-Zulu Natal Wildlife Service, Rowe-Rowe in Otters: Proceedings of the First Working Meeting of the Otter Specialist Group (1977), Lejeune (1989) and Lejeune (1990).

Prey

This otter eats mainly fish, crabs and frogs (plus insect larvae, water bird chicks and molluscs), but the proportion varies throughout the year. In summer, more crabs are taken, though only those less than 50mm across the carapace (to avoid being nipped in the face). In late Autumn and Winter, the drying up of marshes, ponds and backwaters makes frogs vulnerable, and these can form more than 20% of the diet. In the Winter, when crabs hide in inaccessible places, and fish are slower in colder water, the latter become much more important. Lejeune found that only fish smaller than 20cm were taken in the lakes he studied - eels, yellowfish, potted bass, bluegill, largemouth bass and trout. The stomach of a dead otter (accidentally killed) also contained vegetation, as well as numerous internal parasites.

These otters need about 500g of fish per day.

Hunting Schedule

This is unknown for the secretive, nocturnal members of the species, but on the great Lakes, fishing does take place all day, but with peaks in the morning (7 till 10am) and evening (7 till 10pm).

Hunting Methods

These animals hunt by sight, rather than using their whiskers (Davis in Otters: Proceedings of the First Working Meeting of the Otter Specialist Group (1977) considers their vibrissae 'weak'). They catch and carry their prey in their mouths, and eat it on the surface of the water, rather than bringing it to land.

They intensively hunt the centre of their range, foraging alone except when driving fish towards their cubs when teaching them to hunt. As well as diving from the surface, they also forage in semi-aquatic vegetation, and raid fishing nets by night. Less controversially, they have learnt to wait for returning fishermen, and pick up discarded catch.

During a typical day, over a 20 minute period, an average otter makes two dives of about a minute each, resulting in one capture of a fish less than 20cm long. After this, the otter often leaves the water and rests up in dense vegetation. To get their daily food, they average a total hunting time of 100 minutes split into several sessions.

Spotted-Necked Otter