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North American River Otters Mating and Giving Birth

North American River Otters are induced ovulators – copulation releases the female’s egg from the ovary.  Once the egg is released and fertilized, however, there is a nine to eleven month delay before the embryo begins actively developing (delayed implantation). Actual gestation takes about two months. Thus, otters sometimes give birth up to a year after mating, just before their next breeding cycle.  April and May are busy months for this semiaquatic mammal.

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3 responses

  1. Great shot, Mary! Thatr otter looks just like the Lorax.

    May 2, 2022 at 8:18 am

  2. Alice

    Such fun creatures…I didn’t know any of the reproductive info…always learning.

    May 2, 2022 at 8:31 am

  3. Leslie English

    I just finished an excellent book: Tarka the Otter (Henry Williamson, 1920s), considered among the best books on nature, and reread your past otter posts. Have never heard of this interesting characteristic of delayed embryo development!

    May 6, 2022 at 11:46 am

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