Hey! Just because the tortoises subsist on cowpoop doesn't mean that they like the cows, or socialize with them, or go to Prom with them, or anything like that.
So they MIGHT be "endangered" by cow bullying in the lunch room, or after school while they're all waiting for the cow buses and the tortoise buses.
;-)
The turtles could actually enjoy lounging in the shade of a friendly cow on a hot summer’s day.