Everything you wanted to know about eggs 

…and then some. From the eggs of the platypus to the eggs of dinosaurs, we’ll talk about how eggs are formed, why humans don’t lay them, and of course, why the egg definitely came before the chicken. 

Click For Content Warnings

Placentas and afterbirth, body fluids, cursing

Images From the Episode


Wiemann, Jasmina, et al. "Dinosaur origin of egg color: oviraptors laid blue-green eggs." PeerJ 5 (2017): e3706.

Wiemann, Jasmina, Tzu-Ruei Yang, and Mark A. Norell. "Dinosaur egg colour had a single evolutionary origin." Nature 563.7732 (2018): 555-558.

Monotremata: Life History & Ecology. https://ucmp.berkeley.edu/mammal/monotremelh.html

Divljan, A. 2022. Platypus. https://australian.museum/learn/animals/mammals/platypus/ 

Kuruppath, S., Bisana, S., Sharp, J. A., Lefevre, C., Kumar, S., & Nicholas, K. R. (2012). Monotremes and marsupials: comparative models to better understand the function of milk. Journal of biosciences, 37, 581-588.

Weaver, Lucas N., et al. "Early mammalian social behaviour revealed by multituberculates from a dinosaur nesting site." Nature Ecology & Evolution 5.1 (2021): 32-37.

Brawand et al 2008 Loss of Egg Yolk Genes in Mammals and the Origin of Lactation and Placentation

Fresh Eggs Daily. How long for a chicken to lay an egg? https://www.fresheggsdaily.blog/2017/05/how-long-does-it-take-chicken-to-lay-egg.html

The Chicken Chick. How a hen makes an egg & egg oddities. https://the-chicken-chick.com/how-hen-makes-egg-egg-oddities/

Holland, K. 2018. Bright Orange Yolks Don’t Necessarily Mean High-Quality Eggs. Here’s Why https://www.myrecipes.com/healthy-diet/orange-egg-yolks-do-not-mean-healthier-eggs

Freyer, Claudia, and Marilyn B. Renfree. "The mammalian yolk sac placenta." Journal of Experimental Zoology Part B: Molecular and Developmental Evolution 312.6 (2009): 545-554.

Weaver, Lucas N., et al. "Multituberculate Mammals Show Evidence of a Life History Strategy Similar to That of Placentals, Not Marsupials." The American Naturalist 200.3 (2022): 383-400.


Luo, Zhe-Xi. "Transformation and diversification in early mammal evolution." Nature 450.7172 (2007): 1011-1019.

Álvarez-Carretero, Sandra, et al. "A species-level timeline of mammal evolution integrating phylogenomic data." Nature 602.7896 (2022): 263-267.