Polar Bears

I was trying to play mc with my stepdad and it was really laggy. I was heading over to his mine to mine with him and I saw this pile of maybe 20 or so polar bears right outside.so as any normal person would because of the lag we killed them but I needed to know if this was a glitch that has happened to anyone else. Also the polar bears were in the middle of a forest nowhere near a Snowy or icy place