Ladoga ringed seal

The Ladoga ringed seal (Russian: Ладожская нерпа; Pusa hispida ladogensis) is a freshwater subspecies of the ringed seal (Pusa hispida). It lives only in Lake Ladoga in northwestern Russia. This special seal was separated from the Arctic ringed seal because of changes in the land after an ancient ice age, called the Weichselian Glaciation, ended. The land rose up, a process known as isostatic rebound, which trapped the seals in freshwater lakes.

The Ladoga ringed seal is closely related to another small group of seals, the Saimaa ringed seals, who live in Lake Saimaa. Lake Saimaa connects to Lake Ladoga through the Vuoksi River. These two groups are unique because most seals live in saltwater oceans, not freshwater lakes.

Appearance

The Ladoga ringed seal is a special type of seal that lives in Lake Ladoga in Russia. Adult seals grow to be about 150 cm long and weigh between 60 and 70 kg. Baby seals, called pups, are much smaller, about 50 to 60 cm long and weigh around 4 to 5 kg when they are born.

These seals come in four different coat patterns. Most of them, about 47%, have a dark brown coat with lighter ring shapes. Another 29% have a dark brown coat with lighter vein-like patterns. About 17% have a light brown coat with a dark stripe along their back and some faint rings and spots. The remaining 7% have coat patterns that were not described in detail. Every year, from April to June, these seals shed their old fur and grow new one.

Reproduction

Female Ladoga ringed seals grow up and can have babies when they are four to five years old. Male seals are ready a little later, at six to seven years old. Baby seals, called pups, are born between February and March. It takes about six to eight weeks for the mother to teach the pups everything they need to know before they are ready to go on their own. These seals can live for around 30 to 35 years.

Conservation

The Ladoga ringed seal population today is around 2,000 to 3,000, much less than the 20,000 that lived there at the start of the 20th century. This decrease happened mainly because people hunted them too much. Hunting these seals was made illegal in 1980, but sometimes people still break the law and hunt them.

The seals face other dangers too. They can get caught in fishing nets, and human activities like building things near Lake Ladoga and fuel spills from boats can harm them. People enjoying the lake for fun can also disturb their resting spots. The Ladoga seal is protected under important agreements and is listed in special books to help save the species.