Sea otters, the adorable urchin-eating mustelids of the ocean, may be cute, but their relatives the river otters are another story. If this alligator's experience is anything to go by, I wouldn't want to be on the business end of their chompers.

River otters, despite their fairly diminutive stature, are actually considered to be apex predators in their riparian habitats since they have no natural predators. Maybe that explains why this river otter wasn't afraid to take on a juvenile alligator at Florida's Lake Woodruff National Wildlife Refuge. While these photos were originally taken by Geoff Walsh in 2011, they only surfaced on Facebook this week.

Meanwhile, halfway around the world in Queensland, Australia, an olive python fought a freshwater crocodile to the death. It then proceeded to eat its opponent, face-first. Both species are apex predators, but it's not uncommon for mature individuals of one species to prey upon juveniles of the other. Bystander Marvin Muller managed to snag some photos.

While it's not news that snakes can take down prey as big as they are, here's another reminder that nature doesn't always work the way you think it does. I'd expect the pointy end of the croc to easily overcome the constricting action of the snake. You might take a second look at your predictions for Mammal March Madness...

[Lake Woodruff NWR; Brisbane Times via HuffPo]