>>33230506I read a study once that talked about what species survived the K-T extinction and why.
To this day I wish I could find it again because it was absolutely insightful into why so many common traits exist among birds, reptiles, and mammals that flourish today.
Basically the animals that survived were ones that were small enough to have low metabolic requirements, animals that were semi-aquatic and were able to stay submerged underwater during the time of the K-T impact, animals that were in burrows, caves, or sheltered nests (think tree hollows, dens, underground burrows), were able to avoid staying above surface except in minimal circumstances, and weren't so large as to require large amounts of energy to be replenished often.
Consider how many species of mammal have an innate ability to swim or have an innate drive to burrow, create underground dens, or seek out caves to live in.
Why do birds make nests inside of trees?
Of course crocodiles and turtles survived, the smaller species would easily require minimal time above water to not get scorched by the heat wave. The smaller species also required less food as opposed to larger species which is why you would see moasaurs and pliosaurs die off but not turtles or crocodiles.
If I recall correctly, birds and crocs flourished first in the beginning of the Paleocene until mammals took off towards the end of that epoch and into the Eocene.
