The Tuscan raiders
The Walrus Odobenus rosmarus is similar to seals having both pectoral flippers, tail flippers, muzzle and long whiskers. differentiating themselves by having a broad muzzle with large upfront whiskers and two tusks up to 1m in length. the males use the tusks to combat other males and dominate other walrus’s, as well as using them to hall out on to sea ice. it reaches 3.6m in length and weighing up to 4’400 pounds for males and 3000 pounds for females. with notably thick skin which is creased and rough. the tail is enclosed in a web of thick skin and layer and layer of blubber. they are grey –cinnamon-brown in colour getting paler skin later in age turning rosy red when warm. the flippers are short, and they have a square shape to them which can able angled out for movement, the back flippers are triangular with five digits and will push one then the other to allow them to move through water.
Where are they found
The walrus is circumpolar in its range, but found in distinctive areas dependent on their species. The pacific walrus is found in the Bering, Chukchi and Laptev sea. While the Atlantic walrus inhabits the coastal regions of the North-east Canada and Greenland
Maturation + Reproduction
A mystery surrounds walrus maturation and reproduction, as males mature at the age of 8 years but wait to mate till 15 years of age and females reach maturation at 5-6 years but won’t reproduce till 10 years of age.
Mating season takes place between December through to March, where they will consume far less food.
Males will hang around females making noises to convey to females that they want to mate with them and to males that they want to mate with these females. Males will become very aggressive at this time with each other for the right to mate and even the females, hence the scarring upon the necks of the males. With one male reproducing with as many as 20 females. After the season is over the males will go back to their own full male herd’s where the levels of aggression are much less.
Those females ready to reproduce go through estrus a state where there are additional hormones in their bodies, those not in estrus will separate to form their own group.
The embryo will survive within the body for four months before attaching to the placenta then it takes 16 months after this point for it to be able to survive in a habitat at optimal conditions the offspring will be born on land or ice at a weight of 100-170 pounds, instinctively knowing how to swim. they will survive of milk for the first year, after six months however they will feed of food they catch as well as milk. Mother will move from their natural heard to one with other mothers, where they will help to care for other young even nursing orphans. The pup will stay with their mother for up to two years if there is no other pup, but will stay in touch for life.
Natural predators are few and far between. Due to their huge size and their very thick blubber which is 10cm around the neck and 15cm around the rest of the body. This means that to get through that blubber power jaws and claws are required. Which are only possessed by polar bears and orcas. Polar bears have the advantage of speed on land, they are much faster and will target the young, old or elderly. rather than fight a full grown healthy walrus with metre long tusks (though will also wait around air holes). Orcas take advantage of the walrus’s instinct to move towards water when threatened, where they are then waiting for them. Despite the size of walrus’s, the both polar bears and orcas are large carnivores and can consume huge amounts of food.
There is an estimated population of 223,000 walrus’s, separated over three populations. In the Atlantic where there are 18,000, in the pacific there are 200,000 and Laptev there are 5,000
They stay close to the shore but are capable of diving to 260 ft. for food – with a depth time of 30 minutes. They feed mainly of clams and other molluscs, but as opportunistic feeders will feed of shrimp crab worms and corals, but will go as far as consuming seal carcasses and birds if necessary. large males who have become accustomed to eating seals will go after seals preferentially, as it allows them to feel full due to the higher levels of sustenance from seal meat, evident from seal grease stains upon their skin. They use their whiskers, which they push through the sand to find food (they will also use water they suck in and blow out to expose food) to find food and their flippers to handle them, using their strong jaw’s lips and young to suck the meat from a food source. Consuming up to 6% of their food weight every single day which can be as much as 180 pounds.
Social structure within walrus society changes depending on certain conditions. After two years pups will either stay with their mothers if they are female or leave to find an all-male heard if they are male. There is a lot of structure within these herds and are structured through more aggressive means.Males who are ready to mate will also leave their herds to find the herds of females in estrus (they return to their herds after mating however). Those females with pups will find a herd of other females with pups and they will as a group help to rear all the young.