[00:00] When a baby santa Igarshark hatches from its egg, it finds itself trapped inside its mom's uterus. First, to eat in siblings or to be eaten. It's super weird, but pitting your kids against each other can actually sometimes
[00:14] be a winning parental strategy. Hi! I'm Cameron, and this is... ...minute earth... ...Ic.. It's copyrighted... It's common for siblings to fight, for food, for attention, or to establish dominance.
[00:28] And in many cases, parents step in to make sure the rivalry doesn't go too far, not just out of love and whatnot, but because the more babies you have, the more genes you get to pass on. In some species though, parents actually promote a fight to the death.
[00:44] Take black eagles for example. A black eagle pair will always lay two eggs per nest, despite the fact that there's never enough boot around to actually feed two hungry eagle chicks. The scenario forces the chicks to fight for survival.
[00:57] It is brutal, but let's think about it for a second. If the parents had just laid one egg, they'd still need to spend the same amount of time and energy building the nest, defending it from intruders and predators, and incubating
[01:10] the egg. But sometimes that one egg might not have, or the resulting chick might do, sick and die. In those cases, all that work is for nothing. So as long as the parents have to go to all of that trouble, it makes sense to lay two eggs
[01:23] so that one can serve as a backup. If both eggs are healthy, the parents only have to take care of the stronger, healthier one that emerges victorious from the thunder dome. And black eagles aren't alone in this. Some other birds and insect species also bear extra offspring as an insurance policy only
[01:40] to pit the survivors against each other. But the sand tiger shark takes sibling rivalry to an extreme. A mama shark can incubate as many as 20 eggs at a time in her uterus, so theoretically she could birth 20 babies at once, but all of those babies would be way too small to thrive,
[01:56] they couldn't hunt or escape predators. So instead, female sand tiger sharks have evolved reproductive systems that trap their babies inside after hatching, forcing them to snack on their own siblings in order to survive.
[02:08] And after several months, the sole survivor is born. It's now a meter long with a full mouth of razor teeth and ready to take on the open ocean. In contrast to such brutal beginnings, isn't it nice that our human parents,
[02:21] mostly just want us to get along? This video is brought to you by you. That's because you guys have been buying our awesome new animal taxonomy posters by the
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