This species appears to be restricted mainly to primary forest habitats, as high as 2,400 m on the Tsaratanana Massif, as well as primary and secondary coastal rainforest. It does not appear to tolerate degraded habitat well (Tecot 2008). Its activity pattern is characterized as cathemeral, and it can be more frequently recorded during nocturnal than diurnal transects (Holmes et al. 2015). Group size varies from two to six individuals, the typical group containing an adult pair and their offspring (Overdorff and Tecot 2006, Tecot et al. 2016). Home range size has been estimated at 12-15 ha. Young are typically born in September and October (Tecot 2010), after a gestation period of 123–127 days. One infant is usually born per year or in alternate years to each group and mortality is approximately 50%; twinning occurs frequently (Tecot 2010). Weaning occurs at 6–7 months. They are very specialized frugivores, and an important seed disperser (Wright et al. 2012), although they also consume leaves, flowers and invertebrates, which can be important food sources at certain times of year (Overdorff 1993, Tecot 2008).

The range of Eulemur rubriventer extends from northern Madagascar’s Tsaratanana Massif south along the thin strip of east coast rain forest to the Pic d'Ivohibe and the Manampatrana River (Irwin et al. 2005, Mittermeier et al. 2010), although at one time it ranged further south. It does not occur on the Masoala Peninsula. It ranges from 70-2,400 m asl. Over its relatively large range the Red-bellied Lemur is sympatric with four other Eulemur species: E. albifrons in the northern part, E. fulvus toward the middle, and E. rufifrons and E. cinereiceps in the southern part. However, this species appears to be thinly distributed and restricted to intact forests, and is usually considerably rarer than other sympatric Eulemur; additionally, there are signs that this species is becoming rarer.

It has been estimated that there will be a 76% reduction in the species' range from 2000 to 2080 due to climate change alone (Brown and Yoder 2015).

This species is likely affected by national trends in forest habitat loss: Madagascar lost 37% of its forest cover from 1973 to 2014, with an annual deforestation rate of 1.1%/year from 2010 to 2014. Almost half of Madagascar's forest (46%) is now located within less than 100 metres from the forest edge (Vieilledent et al. 2018).

This species is listed on Appendix I of CITES. Though relatively widespread this species appears to be uncommon everywhere, and has declined drastically in number in recent years. It is known to occur in seven national parks (Andringitra, Andasibe-Mantadia, Makira, Marojejy, Marolambo, Ranomafana, and Zahamena), two strict nature reserves (Tsaratanana and Zahamena), six special reserves (Ambatovaky, Analamazaotra, Anjanaharibe-Sud, Mangerivola, Marotandrano, and Pic d' Ivohibe) and other newer protected areas in lower protection categories (Corridor Ankeniheny-Zahamena, Corridor Forestier Fandriana-Vondrozo, and Maromizaha) (Mittermeier et al. 2010, Nicoll and Langrand 1989, Schmid and Smolker 1998). Other populations are found in community-based conservation sites: four groups were located in Vohitrarivo bamboo forest (east of Ranomafana National Park), where they are being monitored by the NGO Helpsimus, and additional groups in Didy forest. Unprotected groups close to the Ankeniheny-Zahamena Corridor are being monitored by local communities supported by The Aspinall Foundation, as are groups occurring within the Corridor itself. The Aspinall Foundation is also proposing to reintroduce the species to the lowland rainforest fragment of Andriantantely in the Brickaville District, from where it has been extirpated in living memory (King and Ravaloharimanitra 2017).

As of 2019, there were approximately 165 individuals reported in zoological collections worldwide, most of them in Europe (ZIMS 2019). Over 140 are held by EAZA institutions, with the population managed for various roles including as an insurance population and as a source for reintroduction or other conservation translocation projects (Johann et al. 2018). Additional captive animals not included in the above figures are held in Madagascar, including approximately 45 in recognised facilities (E. Robsomanitrandrasana in litt. 2016) and probably small numbers in illegal captivity (Reuter and Schafer 2017).