I have scoured the whole of Skull Island and I cannot find any Longtooths. For a while I thought the pirate was refering to vampires, but you can't skin them. Where can I find a Longtooth? I even set by monster spawn to "Often" hoping that a couple would spawn, but no luck.

YOu do not need to find the Longtooths ON Skull Island - you can find them anywhere and they are in fact easier to find elsewhere. I was attacked by Longtooths right next to Talrik - which was convenient!
Hope you get one soon!

Wyv

Thanks Wyv. No luck yet, but I will keep on trying!

Hope you find one soon!!
So many players have wasted time scouring around Skull Island needlessly. I was fortunate, the first time I played this section, I already had a longtooth skin in my inventory when I met up with Talrik. I was instantly able to fulfill that quest and I had gotten that skin way up north near Oakenmir.

Wyv

There's no hurry to do the quest for Talrik by the way; the only reward is a treasure map you don't need, and refers to something in the Lost Sea, where you get only after doing Anephas' Shrine.