Life Cycle and Reproduction of Beluga Whales
The beluga whale is also called “sea canaries” because of their vocalizations and echolocations. They are highly social and intelligent mammals found in Arctic and sub-Arctic regions. They are well-known for approaching humans due to their friendly nature and are famous for their smiling faces. Let’s discuss their lifecycle and reproduction step by step.
Birth and Growth Stages
Seasonal Birth:
Beluga whales are mostly born in early summer and late spring because, during this time, the water in the Arctic and sub-Arctic regions is temperate enough for them. The environment during this period is ideal for the safety and growth of the calves.
Newborn Characteristic:
- A newborn beluga calf measures approximately 5 feet in length.
- The weight of a newborn calf ranges between 41 and 66 kg.
- At birth, the calf’s color is gray or brown.
- The gray or brown coloration provides camouflage, helping the calf evade predators.
|
Characteristic |
Description |
|---|---|
|
Length at Birth |
Approximately 5 feet |
|
Weight at Birth |
Between 41 and 66 kg |
|
Color at Birth |
Gray or brown |
|
Benefit of Color |
Helps the calf evade predators due to camouflage |
Color and Size Changes:
As time passes and they reach one year of age, their color changes to dark gray or blue. As they continue to grow and mature, their color gradually turns white. Males typically become completely white by the age of 9, while females achieve their fully white coloration by around seven years of age. Female belugas are 25% smaller in size and weight compared to males.
Nursing Period:
The calf remains in the mother’s womb for 14 to 15 months, giving belugas the longest pregnancy period among all mammals. Newborn calves prefer to stay with their mothers, who nurse them for 1 to 2 years. The milk is very beneficial for the calves, helping them survive in the cold environment. Calves learn to swim very quickly, as their mothers teach them. They stay with their mothers not only for safety but also to learn essential survival skills.
Physical Growth:
Belugas reach maturity and adulthood between the ages of 8 and 10. An adult male beluga typically measures between 11 to 18 feet in length and weighs between 1,100 to 1,600 kg. Adult female belugas are smaller, measuring between 9 to 14 feet in length and weighing between 700 to 1,200 kg. Their lifetime ranges from 30 to 50 years, provided they are not hunted by predators or humans.
Mating and Breeding Season
Time of Mating:
The mating season mostly occurs from December to March when belugas migrate, as the water temperature is temperate during this time. Most beluga whales become sexually mature between the age of 4 to 7. Females become sexually mature between the age of 4 to 7, while males mature between 7 to 9 years. However, males do not mate until they become socially and physically dominant compared to other males. This does not mean that mating happens only during these months; it is mainly because they tend to mate in winter when the water is temperate.
They mostly mate in bays, rivers, and estuaries where the water temperature is between 10°C and 15°C. During the mating season, the weight of a beluga whale’s testes doubles, and mating typically occurs between 3 to 4 a.m. A female gives birth to one calf every three years. Additionally, after the age of 41 years, a female no longer gives birth.
Breeding Behaviour:
The breeding season for calves occurs in late winter or early spring, meaning between December and March. A female gives birth to one calf every three years, and it is very rare for a female to give birth to twins. The mother nurses her calf for up to 2 years, and this milk helps the calf survive during winter because it is fat-rich. This fat helps form blubber, which aids in surviving the cold.
During the first year, calves prefer to stay with their mothers. The mother keeps them safe from predators during this time and also teaches them how to swim, which is why calves learn to swim very quickly. One year later, their teeth start growing. At this time, their diet consists of shrimp and small fish besides their mother’s milk, which is part of their diet still.
Lifespan and Survival Rates:
Lifespan:
The average survival rate of belugas is 30 to 35 years, while some live up to 40 to 50 years. Belugas’ lifespans depend on social skills, food, and size. Larger belugas, which are bigger in size compared to other belugas, tend to have a longer lifespan than smaller belugas.
Survival Rates:
If we talk about their survival rates, human activities also contribute to their reduced survival rates. Fishing nets and pollution have a significant impact on their survival. Noise pollution reduces their echolocation power, which is essential for their navigation and communication. Climate change and habitat loss also affect their long-term survival. When ice forms, if belugas do not migrate quickly, they can become trapped, which significantly reduces their survival rate. When they are in warm waters, their prey often migrates elsewhere, impacting their food supply. This also reduces their survival rate.
Survival Challenges:
Their main predators are killer whales and polar bears. If they organize to run these predators, they can live peacefully for 30 to 40 years. However, in recent times, their population has been decreasing due to human activities, especially because of excessive pollution, which leads to their deaths.
