The checklist for being a mammal is pretty straightforward: you need to be warm-blooded, you need to have body hair, and you need to nurse your young. So imagine scientists' surprise when they discovered that a spider — an invertebrate that is definitely not a mammal — produces milk and nurses its young.
Related Video: Amazing Facts About Spiders
Jumping on the Mammal-Wagon
Written by Ashley Hamer November 30, 2018
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