Sigmodontines

Sigmodontines are a large and diverse subfamily of rodents belonging to the family Cricetidae. This group primarily encompasses New World rats and mice, found throughout the Americas, from southern Canada to the tip of South America. Their evolutionary history is complex, with many genera and species exhibiting unique adaptations to a wide range of environments, including forests, grasslands, deserts, and even aquatic habitats. The name "sigmodontine" itself refers to the characteristic sigmoid (S-shaped) molar cusps found in many, though not all, members of this group, which are adapted for grinding plant material.

The diversity within sigmodontines is remarkable, with over 400 described species spread across numerous genera. This includes familiar groups like cotton rats, rice rats, and hispid pocket mice, as well as many less commonly known species. Their diets are generally herbivorous or omnivorous, with food sources varying significantly depending on the species and its habitat. Sigmodontines play crucial roles in their ecosystems, serving as prey for various predators and influencing vegetation through their feeding habits. Research on sigmodontines continues to reveal new insights into mammalian evolution, biogeography, and adaptation.