Great question. Firstly neanderthals were smaller than modern humans homo sapiens sapiens (sapiens meaning “wise”). They were around the same height as humans, or maybe a little smaller . They may even have had red hair and light skin! Their heads were definitely slightly bigger but this does not mean for sure that they had bigger brains than us. One thing we know for sure is that we prospered and they did not!
Why is this? Well some believe that we simply interbred and we both evolved closer to each other . Others think that they existed slightly before us and could cope with a changing climate way back then. The finally idea is that there was a volcanic eruption that may have wiped them out.
Hope that answers your question, and adds a little more!
Ahhh, our closest extinct human relatives! Neanderthals’ looked very similar to us, though they were shorter and stockier with angled cheekbones, prominent brow ridges, and wide noses. Great question! Hope we got to answer enough of your questions during our chat earlier, cheers!