Species: Lutra maculicollis
Range and Habitat
The spotted-necked otter lives in Africa south of 10° N latitude. They are found
in most of the river systems in sub-Saharan Africa, but are particularly
abundant in Lake Victoria and Lake Tanganyika. They are absent from the far
western and southwestern regions of Africa. They prefer areas of permanent and
continuous waterways, like rivers, streams, lakes, swamps, and reservoirs, at
higher altitudes. They avoid turbulent rivers and shallow lakes. Areas of thick
vegetation along the waters edge are primary habitat.
The spotted-necked otter looks similar to other river otter species. They can be
distinguished by their distinct markings of brown and white spotting on their
throat and underside, and are otherwise a dark brown to reddish brown in
coloration, with a lighter underside. Like all river otters, the spotted-necked
has a thick, cylindrical, elongated body set on short, stocky legs. They have a
soft, wooly undercoat covered by coarse, shiny guard hairs. These guard hairs
keep the undercoat dry when the animal is wet, keeping the animal warm and
insulated. Unlike other aquatic mammals like seals, otters lack an insulating
layer of body fat, so they rely solely on their fur to keep them warm and dry.
Their head is rounded and flattened, with small, round ears set low on the head.
Their muzzle is short and broad, and rounded in shape, with whiskers that are
less dense than other species of river otter. Some describe their head as being
more marten-like than other otter species, with a less fleshy muzzle and smaller
whiskers. The thick neck is short, and is as wide as the head. They have small,
round eyes that are set high and wide apart.
The thick, conical, muscular tail tapers from the base to the tip. They have
five toes on each foot, and their feet are webbed, with the webbing extending
all the way to the tips of the digits. Their claws are strong, but not very
long. Otter's front legs are shorter than their back legs, and this allows them
to swim better. When otters swim slowly, they paddle with all four webbed paws.
When swimming quickly or diving, the shorter front paws are kept close to the
sides of the body, and the back legs and powerful tail propel then through the
water. The ears and nostrils can be closed when they dive underwater. There is a
prevalent sexual dimorphism in this species. Dental formula is: I 3/3 C 1/1 P
4/3 M 1/2 = 36.
The spotted-necked otter feeds primarily on fish, but also eat crustaceans,
frogs, mollusks, aquatic insects and their larvae. Their diet varies throughout
the year as availability of food items changes. They feed on more crabs during
the summer months. Only crabs less than 50mm in width are taken, to avoid injury
from larger crab's larger claws. In autumn and winter months, drying of marshes
and ponds makes frogs more vulnerable, and can constitute a significant portion
of their diet. In the winter months, crabs become inaccessible and fish are
slower in the cold water, so fish constitute the majority of their diet. They
only feed on fish less than 20 cm in length, including eels, yellowfish, potted
bass, bluegill, largemouth bass and trout. They will eat around 500 g of fish a
day. They will sometimes raid fishing nets, and have even been known to wait for
fisherman to discard unwanted fish.
Their hunting habits are crepuscular. They catch food with their mouths, not
their hands. They will eat their food in the water rather than bringing it onto
Reproduction and Life Cycle
It is thought this otter breeds seasonally, but the season varies throughout its
range. They appear to be polyestrus, as noted in captive animals. While males
and females usually only come together to mate, it has been reported that the
male returns when the cubs are 5 months old to help provide food. Cubs begin to
swim at 8 weeks and are weaned at 12-16 weeks old. They will stay with their
mother until they are a year old, sometimes after the birth of another litter.
Cubs play a game of fetch by tossing an object in the water and diving in to
catch it before it reaches the bottom. It is assumed this allows them to hone
their hunting skills.
The spotted-necked otter is typically solitary. Any groups seen are family
groups consisting of a mother and her cubs. Males have a large home range within
which one or more female's smaller home range are located. This otter has one or
more holts (dens) in its territory, with one of the entrances usually being
underwater. Though they are usually crepuscular or nocturnal, in Lake Victoria
they are diurnal. Though they are solitary, they have be seen foraging in
loosely knit groups of up to 20 individuals. It is thought they may do this to
make it easier to catch fish by keeping the shoal together. Boundaries of
territories are marked with spraint and secretions from the anal glands.
Natural predators include crocodiles, eagles and pythons. They do not compete
for food with the other African otter species.
Otters are hunted for their pelts. Habitat destruction, pollution and over
fishing also take their toll on this otter. Increased turbidity (silt) in the
water from agricultural runoff decreases the ability for them to see in the
water and makes it harder for them to catch prey. Draining freshwater for
industrial and community usage, as well as draining wetlands for agricultural
and housing creates habitat loss. Alien species of fish, such as the Nile Perch
to Lake Tanganyika have created problems with native species of fish, causing
scarcity of food items. Pollution such as sewage, PCB's, and heavy metals from
mining that leach into the water kill off otters as well as their food supplies.
Otters are seen by fisherman as competition for food, and are hunted with dogs.
They sometimes are entangled and drown in fishing nets and traps. In Nigeria,
fisherman put natural and artificial toxins directly into the water to catch
fish, and this kills otters directly and indirectly. They are hunted by
indigenous peoples for food and their skins.
Though they are protected legally in most countries in Africa, these laws are
There are no known subspecies of spotted-necked otter. At one time up to 6
subspecies were recognized, but CITES felt that these were merely regional
variations and not enough of a distinction to warrant subspecies status. The
differences were in tooth size, with the otters in the outer areas of the range
having slightly larger teeth, and ones in the central area of the range having
slightly smaller teeth.
Animal Diversity Web: Lutra maculicollis
Herman Miller photographs (photo credit)
IUCN Red List: Lutra maculicollis
Otterjoy: Spotted-necked otter