[6] The analyses of postcranial fossils by paleontologists suggest that members of the family Paromomyidae, including the genus Ignacius, most likely possessed adaptations for arboreality.

[6][14] During the early Cenozoic, North America experienced multiple climatic changes with the warmest mean annual temperatures (around 16oC, 60oF) occurring during the Paleocene-Eocene Thermal Maximum (PETM) at around 55 Ma.

[15] During the Eocene Climatic Optimum (c. 53 Ma) there was a correlated diversification of flora creating a complex, warm-temperate to subtropical habitat over much of interior North America.

[14] The late Cretaceous and early Tertiary saw a diversification of angiosperms providing the opportunity for arboreal mammals to utilize the fruit, seed, exudate, and flower resources of these plants.

[7] The environment of interior North America, extending into the Canadian Arctic, would have provided habitable ecosystems for these arboreal mammals to thrive and diversify.

[7][17] Some researchers have also hypothesized based on analysis of hand bone morphology, that they possessed gliding adaptations like those of modern-day flying lemurs (Order Dermoptera).

[11] Evidence for vertical climbing can be seen in the morphology of the humerus, femur, and tarsal bones which are consistent with increased flexibility of the shoulder, elbow, hip, knee, and ankle joints.

Flexible lumbar vertebrae as well as increased surface area on the innominate and femur for the origin and insertion of gluteal muscles, suggest paromomyids were capable of powerful bounding across tree branches.

[7][17] The large, procumbent incisors and reduced shearing crests of Paromomyids, especially Ignacius and Phenacolemur, suggest a diet specialized for feeding on exudates, comparable to the adaptions seen in extant callitrichine primates and Petaurus, a marsupial sugar-glider.