AVIAN EGG SHELL PHYSIOLOGY: A REVIEW. J. MICHAEL REED and WILLIAM J. YURKIEWICZ. Proceedings of the Pennsylvania Academy of Science. Vol. 56, No. 1 (1982), pp. 55-60 (6 pages) Published By: Penn State ...

The tough little egg made it all the way through the digestive system of a coscoroba swan like this one. TonyBaggett / iStock. Killifish eggs are known for their resilience: They’ve been found ...