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Related Experiment Video

Updated: Mar 31, 2026

Development of an in vitro model system for studying the interaction of Equus caballus IgE with its high-affinity receptor FcεRI

Development of an in vitro model system for studying the interaction of Equus caballus IgE with its high-affinity receptor FcεRI

Published on: November 1, 2014

Equids.

Ludovic Orlando¹

¹Centre for GeoGenetics, Natural History Museum of Denmark, Øster Voldgade 5-7, 1350K Copenhagen, Denmark.

Current Biology : CB

|October 21, 2015

Summary

This summary is machine-generated.

The equid family, including horses and zebras, has a 55-million-year fossil history originating in North America. Early equids, unlike modern ones, had multiple toes and were soft-leaf browsers.

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Area of Science:

Paleontology
Evolutionary Biology
Mammalogy

Background:

The equid family (Equidae) includes domestic horses, donkeys, asses, and zebras.
Equids possess an extensive fossil record spanning 55 million years, showcasing significant evolutionary changes.
The family originated in North America, with early forms like Hyracotheres being small, multi-toed browsers.

Purpose of the Study:

To outline the evolutionary history and diversification of the equid family.
To highlight key evolutionary innovations and adaptations within equids.
To place equids within the broader mammalian order Perissodactyla.

Main Methods:

Analysis of the fossil record to trace equid lineage and morphology.
Comparative anatomy of extant and extinct equid species.
Phylogenetic analysis to understand equid relationships within Perissodactyla.

Main Results:

Equids diversified significantly during the Miocene, with over twenty genera existing then, compared to the single genus Equus today.
Early equids, such as Hyracotheres, differed markedly from modern equids in size, dentition, and limb structure (four-toed forelimbs, three-toed hindlimbs).
Equids are classified as hindgut fermenters, a digestive strategy distinct from ruminants.

Conclusions:

The equid family exhibits a rich evolutionary history marked by diversification, adaptation, and extinction.
Understanding equid evolution provides insights into mammalian adaptation and paleogeography.
Equids represent a key lineage within the Perissodactyla, characterized by unique digestive and morphological traits.