[ **up: [[Mammals]]** ] --- # Rodents Baby rodents are called *pups*.[^1] --- ## Taxonomy - **[[Life (Biology)]]** - **[[Eukaryotes|Eukaryota (Domain)]]** - [[Animals|Animalia (Kingdom)]] - [[Chordates|Chordata (Phylum)]] - [[Mammals|Mammalia (Class)]] - [[Rodents|Rodentia (Order)]] <small>RODENTS</small> --- ## Description ### Pheromones [[2025-0321. 'Pheromones are typically secreted by specialized glands or tissues.'|’Rodents have a wide variety of skin glands as well as large and small pheromone molecules delivered in their urine.’]][^2] --- ## Reproduction ### Lactation #### Nipples: The “one-half” rule [[2025-0320. 'Mammary number may limit litter size in an evolutionary sense.'|’The one-half rule can be interpreted as a statistical consequence of the frequency distribution of litter sizes. These distributions typically have a lower boundary of one and an upper boundary equal to the mammary number. Because the modal litter size of most species is of an intermediate number, the result is that the mean litter size falls halfway between one and the mammary number. One interpretation of these results is that natural selection has favored mammary numbers adequate for the occasional extreme rather than the more frequent typical litter size.’]][^3] --- ## Rodents (in these notes) - [[African pygmy mouse]] - [[Chestnut climbing mouse]] - [[House mouse]] - [[Lemmings]] - [[Mus musculus domesticus]] - [[Ryuku spiny rat]] - [[Transcaucasian mole vole]] [^1]: Avery Nelson Gilbert, ‘[[Gilbert. ‘Mammary number and litter size in Rodentia_ The “one-half rule”’, 1986.|Mammary number and litter size in Rodentia: The "one-half rule"]]’, *Proceedings of the National Academy of Sciences of the United States of America*, vol. 83, no. 13 (1 July 1986), p. 4828. [^2]: Tristram D. Wyatt, ‘[[Wyatt. ‘Pheromones’, 2017.|Pheromones]]’, *Current Biology*, vol. 27, issue 15 (7 August 2017), p. R741. [^3]: Avery Nelson Gilbert, ‘[[Gilbert. ‘Mammary number and litter size in Rodentia_ The “one-half rule”’, 1986.|Mammary number and litter size in Rodentia: The "one-half rule"]]’, *Proceedings of the National Academy of Sciences of the United States of America*, vol. 83, no. 13 (1 July 1986), p. 4829.