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Eating Your Siblings in the Womb
In sand tiger sharks, embryos eat their siblings in the womb — only the two largest (one per uterus) survive to be born.
Shark
Selachimorpha
Sharks have diverse and sometimes brutal reproductive strategies, from live birth to eating siblings in the womb.
Vital Stats
🏷️ TypeCartilaginous fish (elasmobranch)
🌍 Found InOceans worldwide — from shallow reefs to deep sea
📏 Size17cm (dwarf lantern shark) to 12m (whale shark)
⏳ Lifespan20-100+ years depending on species
🔞 Sexual Maturity5-30 years depending on species
💕 Mating SystemVaries — males often bite females during mating
🤰 Gestation9-22 months depending on species
👶 Offspring1-300 pups (ovoviviparous, viviparous, or oviparous)
🍆 Penis Size30 cm
⏱️ Sex Duration3 minutes
🔬 Notable AnatomyMales have paired claspers; some species have intrauterine cannibalism (embryos eat siblings)
⚖️ Sexual DimorphismFemales often larger; females have thicker skin to survive mating bites