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Wednesday, June 19, 2024

Whale Sets Remarkable Record: Possibly the Longest Pregnancy Among Mammals

humanity still don’t know very much about whales, despite the fact that humanity almost wiped them off as a species. Think about the plight of the bowhead whale.

Bowhead whales can live more than two hundred years, they go into sexual maturity very late, and it takes them to long time to grow, said Nadine Lysiak, a marine researcher who has studied bowheads and other baleen whales for years. But even now, scientists are only beginning to piece together the basics of how creatures like these reproduce. They’re mysterious because they only spend a small percentage of their time above ground.

Dr. Lysiak has been slowly but surely revealing the secrets of the Arctic Ocean’s white-chinned travellers. She and her team may have unearthed a really remarkable phenomenon in nature: female bowheads may carry their young for up to 23 months. That would make it the longest known pregnancy among mammals, surpassing elephant pregnancies by a full month.

Dr. Lysiak thinks that the results might help guide conservation efforts, particularly in light of the impending unfriendly climate, and they were published on Wednesday in the journal Royal Society Open Science.

Researchers have relied on surveys in the field and the examination of dead animals washed up on coasts to learn more about marine mammals like bowhead whales. Dr. Lysiak and her colleagues examined samples from 10 female bowhead whales that were harvested by Inuit in the eastern Canadian Arctic and West Greenland between 1998 and 2011.

The research used baleen, which are the fibrous off-white hairs found in the whales’ mouths. Baleen provides a considerably more holistic view of an animal’s existence than do tissue samples from blubber or skin. These teeth-like projections in the whale’s mouth grow from the gum and store a molecular record of the body’s circulating hormones, functioning as a filter mechanism to keep food in and water out.

Researchers collected small samples of baleen from each whale and analysed their hormone levels, looking specifically for progesterone, which is produced just before and during pregnancy, Despite the researchers’ anticipation that a bowhead pregnancy would last roughly 14 months, the data analysis revealed two progesterone spikes throughout time.

Dr. Lysiak said that he “double and triple checked everything” to ensure his confidence in the accuracy of the calculations and timings being used.

Two possible interpretations were offered by the data. The pregnant period of the bowhead whale is a whopping 23 months. In the other, the whales were not pregnant at the first high levels of progesterone but were instead in a protracted estrous cycle. The second progesterone surge occurred during the marine mammal’s real pregnancy, which lasted around 14 months.

According to what scientists understood about bowhead whale pregnancies, the foetus would be tiny or large in the spring and medium-sized in the autumn if the second scenario played out. However, Dr. Lysiak mentioned a phenomena called delayed implantation, often known as embryonic diapause, that might account for the first scenario.

The pregnancy may be temporarily stopped once the fertilised egg has developed into an embryo. It’s an evolutionary benefit since it lets the mother’s body choose the optimal time to give birth. This break might last anywhere from a few days to 11 months, depending on the species.

While further study is required to confirm a 23-month gestation period for bowhead whales, these results are timely given the plight of the species.

The underlying physiological complexity of these really large, charismatic, but also very ecologically important, species is generally hard to study, and this paper helps us further understand that complexity, according to marine biologist Logan Pallin from the University of California, Santa Cruz who was not involved in the study. Work like this helps us take conservation choices that are based on the best available science.

A Boyle
A Boyle
I cover Science related topics for The National Era
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