# Digestive anatomy and diet of free-ranging maned wolf (Chrysocyon brachyurus)

## TL;DR

This study examines the digestive system and diet of wild maned wolves, confirming their omnivorous nature with a mix of animal and plant matter.

## Contribution

The study provides new empirical data on the anatomy and diet of free-ranging maned wolves, emphasizing their high fiber intake compared to other omnivorous carnivores.

## Key findings

- Maned wolves consume vertebrates (42.5%) and plant material (50.5%) in their diet.
- They ingest higher levels of fiber compared to purely meat-eating carnivores.
- One individual consumed anthropogenic materials like rice and ceramic fragments.

## Abstract

The maned wolf (Chrysocyon brachyurus) is the largest of the currently extant ten species of South American canids and is a monotypic taxon in the genus Chrysocyon, currently classified as Near Threatened by the IUCN. Here we report the anatomy of the gastrointestinal tract (GIT) of 12 free-ranging maned wolves (10 adults, six females, four males, and two juvenile males), nutritional analyses of the gastrointestinal tract (stomach, small, and large intestine) of eight individuals (six females and two males), and the macroscopical examination of the stomach contents of eight individuals (four adult females, two adult males, and two juvenile males). The general anatomy and the dimensions of the maned wolf`s GIT resembled that of other canids. The results of the dietary analyses reported in this study are similar to previously reported data for the species, confirming its omnivorous nature. Vertebrates were found in all stomachs, representing 42.5% of the total dietary mass. Vegetable material was also present in all stomachs, accounting for half of the total dietary mass (50.5%). Anthropogenic material, including cooked rice, glass, and ceramic fragments, were retrieved from the stomach of one individual; such opportunistic feeding behavior has been previously reported. When compared to other Carnivora species classified as omnivores, including the red fox (Vulpes vulpes) and the raccoon dog (Nyctereutes procyonides), these ‘omnivorous’ carnivores ingest distinctively higher levels of fiber compared to purely faunivorous Carnivora. This information might be important for feeding these species in ex-situ settings.

The online version contains supplementary material available at 10.1007/s42991-025-00493-z.