@dw.science: Here’s how a male gets pregnant. In seahorses, the roles are reversed. It’s not the female, but the male that carries out the pregnancy and gives birth to the babies — a unique evolutionary innovation. To make this possible, male seahorses grow specialized brood pouches that act like a uterus and even develop a sort of placenta to provide the embryos with nutrition and oxygen. Scientists have now revealed that it’s not female hormones driving the development of the pseudo-uterus and placenta in seahorses, but male hormones only — so-called androgens. And the research team discovered something else. Male seahorses offer clues about how some species shifted from laying eggs to live birth through evolution. The first step away from simply laying eggs in the wild likely involved sticky eggs that glued themselves onto leaves, or later onto the male’s body. The next evolutionary step was presumably an open or semi-closed brood pouch, which provided some nutrients and safety to the embryos. And finally, the closed brood pouch evolved, the most complex and advanced form of parental care in seahorses. A brood pouch can host up to around 1,000 small seahorse babies. These large litters are needed, as usually only about 0.5% survive. Fun fact: Besides seahorses, male pipefishes and seadragons also take on the pregnancy role — all fish of the Syngnathidae family. Author: Lea Albrecht Study: Liu, Y., Jiang, H., Miao, Y. et al.: Cellular and molecular mechanisms of seahorse male pregnancy. Nat Ecol Evol 9, 2404–2421 (2025). https://doi.org/10.1038/s41559-025-02883-5 #pregnant #seahorse #male #baby #sciencetok #Science #dwscience

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Tuesday 24 February 2026 14:00:12 GMT