Criterial features

Today’s Scenes From a Multiverse: At issue here is what features are criterial for classifying a creature as a mammal. Here’s a list of features common to all mammals; the asterisk marks features that distinguish mammals as a group from reptiles, birds, and amphibians: warm-blooded (endothermic); vertebrate; *with sweat glands; *including mammary glands, those specialized … Continue reading Criterial features