In 2018, the female traveled more than 1,600 km pushing the body of her calf for 17 days. She also gave birth to two other cubs, who are still alive. Before losing her fourth baby, off the coast of the United States.
This is sad news for the Whale Research Center, based in Washington State, United States. Since December 20, specialists have spotted an orca swimming with its dead baby. A behavior already observed in the same female well known to researchers under the name Tahlequah, in 2018, after the loss of a previous cub, reports the British newspaper The Guardian . At the time, she had traveled more than 1,000 miles pushing her calf's body for 17 days.
A “devastating” loss
The research center shared the sad news on its Instagram account this Wednesday 1is January, indicating that the 26-year-old orca and her late calf were seen in the Puget Sound region, an inlet of the Pacific Ocean in the northwest of the United States, two days earlier. As in 2018, the calf, known as “J61,” was a small female. “The death of any calf is a huge loss, but the death of J61 is particularly devastating, not only because she was a female, who could have one day potentially led her own line, but also because of his mother's story (…). The entire Whale Research Center team is deeply saddened by this news.write the specialists.
In addition to her baby lost in 2018, Tahlequah gave birth to another calf in 2010, then a third in 2020. Both are still alive and in good health. On December 23, in a previous post informing that Tahlequah was indeed the mother of the newborn J61, the researchers were however cautious. “The early life of calves is always dangerous, with a very high mortality rate during the first year. J35 [autre nom de Tahlequah, NDLR] is an experienced mother and we hope she will be able to keep J61 alive during these difficult first days”indicated the scientists.
Orcas live in a very polluted area
Six years ago, when her other calf died, the behavior of the mother orca intrigued experts. At the time, Christophe Guinet, research fellow at the CNRS at the Center for Biological Studies in Chizé (Deux-Sèvres) explained to Figaro : “That marine mammals take care of their dead is something that we have already seen and that we know. But over such a long period, this is unheard of! Especially since the female must have eaten very little all this time. Even if her peers probably helped her a little by giving her a few fish”. Female orcas who have just given birth remain permanently with their young and can no longer hunt. They build up their reserves in advance and feed their offspring with mother's milk. After a few days, they start diving again, but the little one stays on the surface. After more than two weeks, Tahlequah had undoubtedly exhausted her reserves.
But for the researcher, the reason for this behavior was linked to the environment. “The area is very polluted, many endocrine disruptors are released into the ocean. It can be envisaged that its production of prolactin [hormone qui joue un rôle dans la lactation et sur le comportement des mammifères, NDLR] was disrupted and contributed to modifying his behavior. But it’s impossible to know for sure.”
Recently, another behavior of the orcas had attracted attention. At the end of October, several orcas were seen again off the coast of Washington state, in the northwest of the country, with dead salmon on their heads. A gesture already observed in 1987. Different hypotheses from scientists try to justify this phenomenon: the orcas could adopt this behavior when they have caught too many fish, or the salmon being perhaps too small to fit under their fin, the orcas would prefer to store them on their heads.
