In the meme and in folklore, yes.

In reality, the meme doesn't hold up.

The true power in the lion pride is in the females. If a male can't finde a pride, he lives alone as a bachelor and has a shorter life span. Lions don't "hold the line" anywhere and can be driven away from prey by hyenas and other scavengers and tend to avoid conflicts (because that risks death and injury.) They're apex predators, so.. they've got the typical bravery of something at the top of the food chain: https://www.pbs.org/wnet/nature/blo.....on-fact-sheet/

But let's talk about the much-maligned sheep.

Sheep aren't that stupid. They're a prey animal that live in groups and can survive well on small resources. Their wariness means that they are very good at surviving (an oblivious animal that doesn't move away from danger doesn't live long.) And it ain't as easy to lead sheep as you might think.

But they're not cowards and are good at defending themselves and members of the flock (just try getting between mama sheep and her lamb.) https://www.lighthousefarmsanctuary.....ts-about-sheep

Lions, on the other hand, don't often turn to defend one of their own - so the "lion as defender of the land" is a folk myth. If you want a "defender of the group", then look to the prey animals.