Gestating

Michael Weiss

Center for Whale Research field biologist, Michael Weiss, thinks it’s a good time to discuss killer whale pregnancy and reproduction. That’s because drone photogrammetry shows females in each Southern Resident Killer Whale pod (J, K, L) are pregnant. 

Earlier this month, Weiss and other scientists reported that J-35 (Tahlequah) is expecting. In July, University of British Columbia scientist Andrew Trites  announced that Tahlequah  had a “baby bump.”  Both Weiss and Trites explain orca pregnancies last up to 18 months. “But for it to show,” Trites says, “the whale has to be quite far along. I suspect that she probably is in the last trimester.” That means Tahlequah’s calf could arrive in January. The world watched the results of her previous pregnancy in 2018. Her calf survived for only 30 minutes after birth, and Tahlequah carried her dead calf for 17 days before releasing the body to the sea.

Supposedly there’s a Southern Resident Killer whale in K pod who’s pregnant, but I couldn’t find any reports about her.  L-72 (Racer) also showed up in drone photographs as pregnant and likely is also in her last trimester.

L72 pregnancy:  Photos by SR3 and NOAA’s Southwest Fisheries Science Center in 2019 and SR3 and SEA in 2020, collected under NMFS research permit 19091.

So, if you want information about what gestation and the newborn stage is like for SRKWs, visit Michael Weiss’s overview in the online newspaper, Orcas Issues. Here are a few of the facts I found most intriguing in Weiss’s article:

  • Killer whale pregnancies last 18 months, one of the longest gestations of any mammal. 
  • At birth, calves (whale babies) are around 8 feet long and weigh about 400 lbs. 
  • Newborns suckle for short periods, dozens of times a day. 
  • Calves may start experimenting with solid food at a young age, but they likely don’t fully wean until age 3.

Weiss also points out the grim realities of low reproductive and survival rates of Southern Resident killer whales.  Fecal samples show that approximately 69% of Southern Resident pregnancies result in spontaneous miscarriage. Of calves that survive, they have about a 1 in 5 chance of living for more than a year. For Tahlequah’s sake, and that of all the endangered SRKWs, I hope she (and all the other pregnant whales) will beat the odds with her present pregnancy.

Let’s all send our collective thoughts for healthy gestations and births for these magnificent, part-time residents of the Salish Sea.

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