[1]: 21  The genus was slightly larger-bodied than any modern peccaries, with an estimated mass of 68 kg (150 lb).

[2] Isotope and anatomical studies have suggested that the diet of Mylohyus varied over geological time, from being primarily a C3 browser during the Blancan, with an increasing consumption of C4 vegetation during the Irvingtonian, with a relatively even mixture of C3 and C4 during the Rancholabrean.

[3] Mylohyus was able to coexist with close phylogenetic relatives because of efficient niche partitioning between it and other genera of peccaries.

[1]: 21 During the last glacial, long-nosed peccaries, sensu lato, were distributed throughout southeastern North America with concentrations in Appalachia and Florida.

Most fossil localities containing this species are found in the southern and south-eastern U.S., from west Texas to Florida, and north to Pennsylvania.