American Spiny Rat

What are the different genera and species that make up the American spiny rat family?

The American spiny rat family, Echimyidae, consists of at least 80 living species organized into 18 surviving genera, which are further divided into three subfamilies.¹

Subfamily Eumyospinae (52 species, 9 genera)

• Proechimys: 32 terrestrial, nonburrowing species.
• Trinomys: 9 terrestrial, nonburrowing species.
• Mesomys: 4 arboreal species.
• Clyomys: 2 burrowing species.
• Carterodon: 1 burrowing species (Owl’s spiny rat).
• Euryzygomatomys: 1 burrowing species (guiara).
• Hoplomys: 1 nonburrowing species (armoured rat).
• Lonchothrix: 1 arboreal species (tuft-tailed spiny tree rat).
• Thrichomys: 1 nonburrowing species (punare).

Subfamily Echimyinae (22 species, 6 genera)

• Nelomys: 8 arboreal species.
• Makalata: 4 arboreal species.
• Echimys: 3 arboreal species.
• Diplomys: 3 arboreal species.
• Isothrix: 3 arboreal species.
• Callistomys: 1 arboreal species (painted tree rat).

Subfamily Dactylomyinae (6 species, 3 genera)

• Dactylomys: 3 species.
• Olallamys: 2 species.
• Kannabateomys: 1 species.

Where are American spiny rats primarily found in the wild?

American spiny rats are primarily found throughout Central America and South America, with a geographic range extending from southern Mexico down to Paraguay and southeastern Brazil.¹

Their specific habitats vary based on the species:

• Tropical Rainforests: Most species inhabit these dense, humid environments throughout Central and South America.¹
• Savannas: Certain species, such as the punare (Thrichomys apereoides), the guiara (Euryzygomatomys spinosus), and those in the genera Clyomys and Carterodon, are adapted to the savannas of eastern and southern Brazil and Paraguay.¹

Within these regions, they seek shelter during the day in various locations, including burrows, tree hollows, brush piles, or among rocks and tree roots.¹

What are the feeding habits and diet of American spiny rats?

American spiny rats are primarily herbivorous, though their specific diet can vary depending on the species and their environment. Generally, their diet consists of:

• Plant matter: They consume leaves, shoots, nuts, and fruit.
• Fungi: Many species include various types of fungi in their diet.
• Insects: They are known to supplement their plant-based diet with insects.

A notable exception within the family is the group of American bamboo rats, which includes the genera Dactylomys and Kannabateomys. These specialized rodents show a strong preference for the shoots, leaves, and stems of bamboo.¹

How do American spiny rats differ from other rodent species?

American spiny rats (family Echimyidae) are distinguished from other rodents by several unique physical and biological characteristics:

• Bristly Coat: Most species possess a coat of flat, flexible spines, which has earned them names like “hedgehog rat” or “porcupine rat.” While a few species have soft fur, this spiny adaptation is their most defining feature.¹²
• Autotomy: A notable survival trait is that their tails break off easily when pulled. Consequently, many individuals are found with stubby or missing tails.¹
• Taxonomic Classification: They belong to the suborder Hystricognatha, a group of “porcupine-like” rodents. This distinguishes them from the more familiar “true” rats and mice, which belong to the family Muridae within the suborder Myomorpha.¹⁴
• Diversity of Form: Unlike many uniform rodent groups, American spiny rats exhibit extreme variation in appearance, ranging from the plain, dull-brown punare to the highly patterned, multi-colored painted tree rat.¹

While they share general rodent features like large eyes and long whiskers, their evolutionary history in South America dates back to the Oligocene Epoch, setting them apart from many other rodent lineages.¹