This was a delightful hat to knit from brim to crown! The yarn is a dream, the pattern is fun and the hat fits me perfectly! I did modify the pattern a bit, based on some people's notes on Ravelry. I added a total of 7 rows to the hat; I also used one needle size larger than called for.
This would be a great hat pattern for your biology- or fossil-loving friends. And I definitely recommend this yarn for hats or any other winter accessories.