Whales are classified as mammals due to their viviparity and because they have milk-producing mammary glands for feeding their babies. As mammals, they are able to support the young for as long as they develop in their womb.
Whales usually gestate one calf at a time. The reproductive rate of these cetaceans is much lower compared to that of other mammals or even other aquatic species, which have much more prolific reproductive patterns determined by shorter gestational periods.
Despite this, the reproductive strategy of whales (known as selection K) is quite efficient for the species. And it is that they only give birth to one calf at a time, but they have a very long life expectancy (some whales live more than 100 years), which is also determined by very little mortality in the first years of life.
How Long are Whales Pregnant?
The gestation period in whales ranges between 9 and 16 months, Different Whale species have different gestation periods.
Blue Whale Gestation Period
The gestation period in blue whales is 10 – 12 months. Blue Whales have an average gestation period of 11 months.
Killer Whale Gestation Period
The gestation period in killer whales is 15 – 18 months. Killer Whales have an average gestation period of 16.5 months.
| Species | Gestation Period |
|---|---|
| Dwarf Sperm Whale | 10 Months |
| Bowhead Whale | 10 – 12 Months |
| Humpback Whale | 11 Months |
| Gray Whale | 12 – 13 Months |
| Beluga Whale | 14 – 15 Months |
