The sea lion body is adapted for life in water and on land. The head is rounded
and tapers down to the hind flippers. They have large eyes and small ears, like ...
ORDER
CALIFORNIAN SEA LION PINNIPEDS
ORDER Pinnipedia
FAMILY Otariidae
GENUS & SPECIES Zalophus californianus
HABITAT
COASTAL WATER
DIET
FISH EATER
STATUS
5 NOT AT RISK
FACTS & FIGURES MALE Total body length Weight Pregnancy Young born Life span
220 – 250cm 275 – 340kg
FEMALE
180 – 200cm 91 – 144kg 11 months 1 pup every year 10 – 15 years (25 - 30 in captivity)
DESCRIPTION The sea lion body is adapted for life in water and on land. The head is rounded and tapers down to the hind flippers. They have large eyes and small ears, like scrolls. The whiskers are long and pronounced to enable the sea lion to feel the changes in water currents when feeding in murky water. The water changes alert the sea lion to fish or octopus, potential prey. The bones in the hands and feet are elongated, decreasing in length. The digits are jointed
by a layer of skin which helps to propel them through the water. Sea lions use their flippers like paddles with the hind flippers used as a rudder. The body is covered with dense fur which is dark brown when wet and dries to a reddish-brown. When sea lions moult, the blood supply to the skin has to be increased to encourage new hair growth – this means heat loss. During this time most sea lions stay out of the water and conserve heat by lying close together. The underfur is moulted first.
Enlarged Vertibrae support the large muscles used in swimming and walking on land
POINTS OF INTEREST Because sea water is always colder than blood temperature, sea lions need effective insulation. Firstly the coat is made up of a guard hair surrounded by a number of shorter fibres and a pair of oil glands. The glands make the fur water repellent and therefore air can be trapped next to the skin of the animal even in water. There is also a layer of blubber or fatty tissue which not only acts as insulation but gives energy during times of little food. Sea lions can close their nostrils and ear flaps when submerged in water. They also
have a soft pallet which seals the throat area so that they can open their mouths to catch prey under water. Sea lions increase their rate of breathing before diving therefore enabling more oxygen to reach the blood. The blood contains more haemoglobin, i.e. the oxygen carrying capacity is three times greater than in man. When diving, the heart rate slows and the blood flow is mainly sent to the brain. A Californian Sea Lion can dive to a depth of 73m but 250m after training.
NATURAL DIET Sea lions feed on a variety of fish, octopus and crustaceans. They concentrate on areas where rising currents carry nutrients to the surface, feeding in the open sea and on the sea bottom. They take whatever food is most abundant and easy to catch. Their eyes have no duct to remove tears which is why their eyes appear so lustrous and often look as if they are crying. The eyes are adapted for low light
conditions and are backed by a reflective tapetum, as in cats. Sea lions can see clearly on land and in the water but in air the pupil contracts to a vertical slit. Their hearing is acute and their sense of smell enables them to find their pup after a fishing expedition. The whiskers play an important part in their feeding by detecting the water displacements produced by swimming fish.
LONGLEAT DIET Summer – As the Longleat sea lions are in fresh water they are given sodium or salt tablets, in their diet. Each sea lion is fed 4– 7kg mackerel plus 8 slow sodium tablets and 3 vitamin tablets daily. As you will see they are always active, playful and curious.
Winter – As the summer, the sea lions are fed a diet of vitamin enriched mackerel each day.
COMMUNICATION
© Longleat
Calls vary from a barking, honking noise to the bellow of a bull defending his territory. On land, the weight of the sea lion is supported clear of the ground by the foreflippers. The hind flippers turn forwards under the body. Only the heel of the foot is on the ground with the toes held up. The sea lion can move quite fast on land and can outpace a man. The breeding season lasts from May to August during which time a male mates as many times as he can. The male marks out a territory or rookery after the pups are born. Many of the prime
sites are chosen at the base of steep cliffs with little beach area. This enables the male to patrol his territory mostly in the water, therefore saving energy, with his females safely on the beach. The pup is born with a woolly coat which is moulted after 2 or 3 weeks. By this time the pup has laid down some blubber to counteract heat loss. The mother feeds her pup in between fishing trips. When she returns from the sea she calls her pup who will reply. The pup is dependent on the mother for 4–6 months but can continue to receive milk almost until the arrival of the next pup.
WORLD DISTRIBUTION CALIFORNIAN SEA LION – The West Coast of America from British Columbia to the tip of Baja California and in the Sea of Cortez.
CONSERVATION Many sea lions were hunted almost to extinction in the 19th Century. They were killed on the coasts of California to provide oil. The blubber was minced and boiled and the skins were used for making glue. The South American Sea Lion has been hunted from the 16th Century and they are still exploited under government control.
The main threat to the Californian Sea Lion is pollution and fishermen. There are about 50,000 sea lions, living in the wild.
© Longleat
DID YOU KNOW? Sea lions have external ear flaps and seals do not.
tails only and hold their flippers close to their sides.
Sea lions are generally larger with a blunt snout. Seals tend to have a pointed nose.
Sea lions groom themselves by using the nails on their hind flippers whereas seals will use their front flippers.
Sea lions can swing their hind flippers forward and can ‘walk’ on land. Seals use their front flippers only and ‘hump’ along on their chest.
Seals can dive deeper than sea lions and empty their lungs. Sea lions retain some air in the lungs when diving.
Sea lions swim using their flippers with the tail as a rudder whilst seals use their
