Crossley’s Dwarf Lemur, Cheirogaleus crossleyi
CROSSLEY'S DWARF LEMUR
Cheirogaleus crossleyi
Geographic Distribution and Habitat
Crossley’s dwarf lemurs, also known as furry-eared dwarf lemurs, are named for the distinctive furry ears that set them apart from other dwarf lemur species. Like all lemurs, they live only on the island of Madagascar, a globally recognized biodiversity hotspot off the southeastern coast of Africa.
While their full range is still being studied, individuals have been observed in forests across northern, central-eastern, and southeastern Madagascar. In the north, they inhabit protected areas like Marojejy National Park and surrounding forests. In central-eastern Madagascar, they occur in high-altitude and mid-elevation rainforests, including those near Andasibe, Tsinjoarivo, and Ambohitantely. In the southeast, they have been recorded in Ranomafana National Park, though researchers are still investigating whether multiple dwarf lemur species may be present there.
As an arboreal species, Crossley’s dwarf lemurs rely on trees and shrubs for movement, foraging, and nesting. Their preferred habitat is undisturbed rainforest, but as these forests become increasingly rare in Madagascar, they are more often found subsisting in degraded forests and even on plantations.
Ten distinct dwarf lemur species are currently recognized by the IUCN, one of which was even assigned its very own separate genus. Revealing this impressive biological diversity has been a long and complex journey. The first dwarf lemurs were described by western researchers as early as 1812. While there was always an understanding that more than a single species existed, our understanding of the full biological diversity of the genus Cheirogaleus was held back for much of history by an over-reliance on museum specimens combined with a considerable lack of field research.
Recent advances in genetic research have significantly helped us refine our understanding of dwarf lemurs, however, revealing in 2009 that this genus is actually a great deal more diverse, with several species occupying smaller geographic ranges than originally believed. Therefore, while the Crossley’s dwarf lemur was one of the three species identified early on in this saga, its range is now understood to be considerably smaller than previously believed.
Size, Weight, and Lifespan
Due to many distinct species going unrecognized until recently, the data for dwarf lemurs is somewhat convoluted. Therefore, the average size and weight of a Crossley’s dwarf lemur is a bit unclear. In general, dwarf lemurs are small primates, weighing only a few ounces (<3 kg). They are bigger than mouse lemurs and smaller than sportive lemurs. Their tails are impressively long, measuring 85-110% of their body length. Crossley’s dwarf lemurs are on the larger end of the spectrum for dwarf lemurs, with an average body weight of 12.3 ounces (350 g).
Current research does not make the average lifespan of dwarf lemurs explicit. However, their reproductive strategy, which prioritizes producing multiple offspring rather than investing heavily in individual young, suggests they may have a relatively short life expectancy in the wild compared to other primates.
Appearance
Dwarf lemurs have a distinct ‘prosimian’ appearance, characterized by their small bodies, large eyes that seem almost too big for their heads, and tiny nimble fingers that prominently grasp the branches they navigate. Their remarkably long tails add something unique to their charm.
In terms of coloration, dwarf lemurs tend to have a neutral pelage that helps these small, vulnerable creatures avoid unwanted attention from predators. Crossley’s dwarf lemurs, however, are a bit on the flashier side, sporting reddish-brown fur on their backs, with light brown fur covering their undersides. While some dwarf lemur species are decorated with a black stripe down their backs, the backs of Crossley’s dwarf lemurs are plain.
The same red-brown coloring on their backs extends to much of their face. Two thick black rings frame their large eyes, while black fur continues down the sides of their snout, reaching all the way to the wet, brown nose (known as a ‘rhinarium’ in prosimians). While the exact patterning varies between individuals, their unique facial mask, along with their noticeably dark furry ears, makes Crossley’s dwarf lemurs distinctly recognizable compared to other dwarf lemurs.
Although they are more colorful than other species, it’s important to note that their coloration likely suits the palette of the specific niche ecosystem where they evolved; additionally, under the cover of night, when dwarf lemurs are active, these colors will appear considerably dull.
Diet
The main staples of a dwarf lemur’s diet are fruit and flowers (nectar), which they favor depending on the time of year. Madagascar’s tropical climate has only two seasons per year (unlike New England’s four): a dry and a wet season. Flowers and fruit grow in abundance during the island’s wet season, while food sources can dwindle to nearly nothing during the dry season.
To survive this challenging period, wildlife species often evolve specialized abilities to find alternative food sources. Dwarf lemurs have taken a surprisingly different route, however; they hibernate! This ability makes them the only obligate hibernating primates known to science!
During the wet season, dwarf lemurs take advantage of the rainforest’s bounty, filling up on nectar, fruit, and invertebrates to prepare for hibernation during the dry season. While some research has noted that dwarf lemurs rely more on nectar as they prepare for hibernation, there may be variation between species and habitats in terms of preference and availability. Some dwarf lemur species have been observed licking nectar from a single flower for up to seven minutes. They obviously have a taste for the stuff!
The specific fruits and flowers that Crossley’s dwarf lemurs rely on have not been identified, and more research is needed to understand their foraging preferences.
Behavior and Lifestyle
Crossley’s dwarf lemurs are tree-dwelling primates. Though they may not look like much, their tiny, nimble fingers are adept at grasping the branches they navigate firmly and their long tails give them impressive balance as they clamber up and around on them. Small and light in weight, they are able to navigate the thicker branches of the canopy as well as the thinner branches of the understory, making both habitats accessible for foraging and nesting.
Dwarf lemurs’ small size makes them vulnerable to predation by carnivores like Madagascar’s endemic fossas and native ring-tailed mongooses, so they have developed several adaptations and behaviors to help them remain hidden. Key to this strategy, known as ‘crypsis,’ is their (mostly) solitary lifestyle. While many primates adopt a safety-in-numbers approach, traveling and foraging in large groups, this tends to make them more conspicuous—larger and louder. In contrast, cryptic species like dwarf lemurs minimize the risk of drawing attention to themselves by choosing to forage alone.
Dwarf lemurs further ensure their ability to remain undetected by being active at night. Not only are they less noticeable under the cover of darkness, but the number of potential threats is also greatly reduced. During the day, they nest in tree hollows, which they line with soft leaves for bedding. In the absence of a hollow, they may create a leaf-litter nest in the underbrush; however, this option seems less than ideal for such a vulnerable species and could be more of a response to a lack of optimal habitat than a preference.
During Madagascar’s dry season, sometime between April and November, dwarf lemurs forego activity altogether and enter hibernation. They are the only true hibernating primates, and curiously, this unique ability is made possible by their impressive tails, where they store all the fat that will sustain them during this period of complete inactivity.
Fat-tailed dwarf lemurs (Cheirogaleus medius) hibernate in the same sorts of tree hollows they sleep in during their active months. However, research has since revealed that other species, notably Crossley’s dwarf lemurs, prefer a different strategy: underground burrows, which they dig themselves.
For a long time, studies focused primarily on fat-tailed dwarf lemurs, leading to the assumption that all dwarf lemurs hibernated in tree hollows. But it turns out that where and how they hibernate depends largely on their habitat.
In the dry deciduous forests of western Madagascar, where fat-tailed dwarf lemurs live, tree hollows offer little insulation. However, the lemurs can still take advantage of natural temperature shifts—warming up passively each day without needing to wake from hibernation.
In contrast, Crossley’s dwarf lemurs and other eastern species inhabit rainforests, often at higher altitudes, where temperatures remain consistently cool during the wet season. In these conditions, tree hollows offer little insulation, making them unsuitable for hibernation. Instead, these lemurs dig underground burrows, where the soil provides a more stable and insulated microclimate. The rainforest soils in these regions are rich in humus, giving them a structure that holds together well—perfect for burrowing. By comparison, the drier, sandier soils of fat-tailed dwarf lemur habitat are poorly suited for burrow construction, explaining why those lemurs rely on tree hollows instead.
Dry conditions also last longer in western Madagascar, which means fat-tailed dwarf lemurs hibernate a good deal longer, up to eight months out of the year! By comparison, eastern species only hibernate 3-6 months, likely based on local conditions.
Interestingly, genetic research strongly suggests that dwarf lemurs originally evolved in these high-altitude rainforest habitats. If true, burrowing may be the ancestral hibernation strategy, while tree-hollow hibernation represents a later adaptation to drier environments.
When you think of hibernation, you probably picture bears or groundhogs escaping the winter cold. But recent research on dwarf lemurs—the only obligate hibernating primates—has challenged this idea. Unlike their northern counterparts, these tropical lemurs don’t hibernate because of freezing temperatures; they do it to survive extreme food scarcity during Madagascar’s dry season. They are one of the few animals in the tropics known to hibernate, and their unique strategy is reshaping our understanding of this fascinating behavior.
Anecdotal evidence suggests that dwarf lemurs occasionally share sleeping sites with tenrecs, Madagascar’s endemic relatives of hedgehogs.
The specific group dynamics of Crossley’s dwarf lemurs are not well studied, but they likely resemble those of their slightly more researched cousins, the fat-tailed dwarf lemurs. Similar to other cryptic primate species that have received limited attention, it was long assumed that dwarf lemurs were solitary and that encounters occurred only by chance or for mating. However, research has revealed that a cryptic lifestyle does not necessarily mean that these primates are asocial.
Dwarf lemurs live in family units composed of two parents and their offspring, though this social structure may not always be apparent. Family units tend to stay close but not too close; while they may forage at the same site or even sleep together in the same tree hollow—especially when their offspring are still young—individuals often fly solo.
Despite significant overlap in their ranges, both male and female parents keep their own territories. Adult offspring have also been observed foraging alongside their parents and younger siblings, and may even babysit on occasion. However, during the dry season, everyone in the group hibernates alone.
In many cases, dwarf lemurs are sympatric with other types of lemurs, including different dwarf lemur species. Just how these various dwarf lemur lineages have evolved separately within the same habitat is a fascinating question that researchers are still actively investigating.
Social creatures like primates need to communicate information about their environment and internal states to others of their species. This communication can take various forms, including vocalizations, body language, facial expressions, hand gestures, and even olfactory signals. Depending on their survival strategies, different species favor different modes of communication.
Dwarf lemurs are known to produce several vocalizations, such as defensive snorts and whistling calls. However, their vocal repertoire is likely more diverse, and research has yet to explore the full range of sounds they produce and their intended meanings.
Like many cryptic species, dwarf lemurs rely heavily on their olfactory sense, using scent-marking as a way to communicate their presence, establish territories, and maintain contact with family members. Unlike other primates that have evolved specialized glands to produce strong-smelling substances for marking, dwarf lemurs keep it simple: they use their feces, rubbing it on the trees and branches they wish to mark.
A male and female form the foundation of dwarf lemur family units. To the best of our knowledge, mating pairs of dwarf lemurs appear to be monogamous. However, this may be influenced more by their generally high mortality rate, which creates opportunities for new pairings to occur long before existing relationships have had the chance to grow stale.
Dwarf lemurs deviate from the typical reproductive strategies seen in other primates. Most primates have a reproductive strategy that prioritizes quality over quantity, with parents investing significant time and energy in raising a small number of offspring to help ensure their survival into adulthood. As a result, these species typically have relatively long lifespans, develop slowly, and require extensive care. In contrast, dwarf lemurs tend to maximize their reproductive output, with females giving birth to at least two, and sometimes three, young per season, though it is unlikely that all of their offspring will survive long enough to reproduce themselves.
Due to the limited time before each family member goes into isolated hibernation, the young must grow quickly. Mothers carry their newborns around for only a few weeks before letting them navigate the canopy on their own. Young dwarf lemurs are already weaned within the first two months of life. Interestingly, despite this deviation in reproductive strategy, both parents cooperate in caring for their young, sharing responsibilities for feeding, grooming, and accompanying them while foraging. Occasionally, even adult siblings have been observed helping to look after their younger siblings.
Much of what we know about the reproductive cycles of dwarf lemurs comes from research on fat-tailed dwarf lemurs. By comparing two populations of fat-tailed lemurs living in different habitats, researchers have deduced that habitat—rather than genetics—plays a key role in shaping the life history traits of these lemurs. Therefore, we should be cautious in assuming that Crossley’s dwarf lemurs, or other dwarf lemur species, won’t surprise us with their unique behaviors.
As fruit eaters, dwarf lemurs likely assist in seed dispersal. The seeds from the fruits they consume travel through their digestive tracts, ultimately falling to the forest floor in their feces, away from the spot where they were originally ingested. This process helps maintain healthy forest ecosystems. Small nectar-eating primates often play a crucial role in pollinating the flowers they visit, but this has yet to be thoroughly researched in dwarf lemurs.
Given their behavior of scent marking with feces, some researchers speculate that dwarf lemurs could even contribute to the creation of microhabitats for specialized plant species, though this idea has yet to be thoroughly studied. Since feces can enrich the soil with nutrients, exploring this aspect of their ecology could provide an intriguing avenue for future research.
The Crossley’s dwarf lemur is classified as Vulnerable by the International Union for Conservation of Nature (IUCN, 2020) and appears on the IUCN Red List of Threatened Species.
Crossley’s dwarf lemurs, like Madagascar’s countless other endemic species, face severe threats from habitat loss and degradation. Between 1973 and 2014, the island lost 37% of its already dwindling forest cover. Much of what was once biologically rich rainforest, home to rare and highly specialized species, has been cleared and replaced with crop monocultures—often rice. For arboreal species like dwarf lemurs, the loss of their forest habitat is devastating. These animals not only rely on the canopy and understory to navigate their range but also depend on mature trees with hollows for nesting.
For decades, slash-and-burn agriculture has been the dominant land-use practice in Madagascar. This unsustainable method involves cutting and burning forests to clear land for farming. While the initial burn releases nutrients into the soil, the benefits are short-lived. Within just a few years, the land becomes infertile and prone to erosion. As a result, species-rich ecosystems are being transformed into farmland that remains productive for only a fraction of the time it took them to develop. Once lost, these ecosystems can never fully recover, and the wildlife they supported—including dwarf lemurs—faces an uncertain future.
Habitat fragmentation—where patches of habitat remain but are disconnected from one another—presents its own set of challenges, especially for tree-dwelling primates like dwarf lemurs. When a once-expansive forest becomes fragmented, dwarf lemur populations are isolated, limiting their access to food and other critical resources. This not only reduces their chances of thriving but also forces them into increased competition with one another, which can become physical and potentially deadly.
Additionally, fragmentation restricts their pool of potential mates, leading to genetic bottlenecks. As genetic diversity declines, populations become less viable, with individuals less likely to survive to reproductive maturity. Because dwarf lemurs reproduce and develop relatively quickly for primates, genetic bottlenecks may have the chance to develop more rapidly, heightening the urgency of addressing this threat.
On top of habitat loss and fragmentation, the Crossley’s dwarf lemur also faces direct threats from hunting and the illegal pet trade. Poaching primates often involves the killing of the mother and, in many cases, other members of the family group. As a result, several individuals may be lost so that a single animal can be captured and sold. Furthermore, primates—especially nocturnal species like dwarf lemurs—do not make suitable pets. Most buyers lack the knowledge and resources to properly care for them, leading to extreme stress, malnutrition, self-harm, and premature death. For those lucky enough to be forfeited or rescued, rehabilitating and returning primates to the wild is not only time-consuming but also complex with no guarantee of success.
Endemic to Madagascar, Crossley’s dwarf lemurs already occupy a small and fragmented range. It is one of several species within the dwarf lemur genus, a group that exemplifies the fascinating and complex processes of natural selection. Each species of dwarf lemur fills a distinct ecological niche, yet little research has been conducted on the nuances of their roles and interactions within their ecosystems. This lack of research poses a threat in itself, as it limits our ability to fully assess the pressures they face—something that has often led to species being underestimated in terms of conservation urgency—and hinders meaningful action to protect them.
Crossley’s dwarf lemurs represent a unique lineage that is not only key to understanding dwarf lemurs but also to broader evolutionary processes and ecological interactions—including our own connection to nature as humans. Therefore, conserving this species and the habitats it depends on is paramount. Since the discovery of several new dwarf lemur species—previously thought to be Crossley’s dwarf lemurs—the recognized geographic range of this species has been significantly reduced, further underscoring the urgency of its conservation.
Crossley’s dwarf lemur is listed on Appendix I of the Convention on International Trade in Endangered Species (CITES), an international agreement between governments whose goal is to ensure that international trade in specimens of wild animals and plants does not threaten their survival. It is believed to inhabit several protected areas, including four national parks (Marojejy, Mantadia, Ranomafana, and Zahamena), the Zahamena Strict Nature Reserve, the Analamazaotra Special Reserve, Ambohitantely Reserve, Ankafobe Forest, the Makirovana-Tsihomanaomby complex, and the COMATSA corridor in northern Madagascar.
At this time, there are no targeted conservation initiatives for Crossley’s dwarf lemurs or dwarf lemurs in general. However, research—particularly field studies—has increased significantly in recent years. Their fascinating behaviors have likely contributed to growing scientific interest and may also help make them more charismatic to the public than they initially appear.
Fortunately, because many lemur species play crucial ecological roles and often share habitats, targeted initiatives are not always necessary for their conservation. Protecting and restoring forests already goes a long way, and many organizations are working toward this goal. The Lemur Conservation Network, for instance, unites over 60 conservation groups that lead community-based projects across Madagascar.
Wildlife Madagascar is one such project dedicated to protecting the country’s rich biodiversity. Their efforts include habitat protection and management—such as patrolling protected areas and monitoring wildlife populations—along with community support initiatives that improve food security and create jobs through ecotourism. The forests they safeguard provide critical habitat for many lemur species, including the Crossley’s dwarf lemur.
In 2021, during the COP26 United Nations climate summit held in Glasgow, Scotland, Madagascar committed to a global pledge aimed at “halting and reversing” deforestation by 2030. While halting this trend is key to conserving dwarf lemurs, it is much easier said than done. As a developing country, many Malagasy people face poverty in their daily lives, leaving them with limited options for how to make ends meet. To survive, they often have no choice but to engage in practices like slash-and-burn agriculture that devastate their unique island ecosystems. There is no easy solution to this dilemma. Education is simply not enough.
Complicating matters further is the risk of biodiversity leakage, a phenomenon where strict environmental regulations in wealthier nations drive industries to shift operations to regions with weaker protections. As these nations work to restore their own biodiversity, demand for timber, agricultural land, and rare minerals often fuels habitat destruction elsewhere, particularly in countries where conservation efforts face financial and political obstacles. Without safeguards, this displacement can undermine global conservation progress.
Critically, the regions most vulnerable to biodiversity leakage are often the most ecologically valuable. Studies show that protecting biodiversity hotspots—regions with exceptionally high species richness and endemism, like Madagascar—yields disproportionately high conservation benefits. These areas not only support unique and irreplaceable species but also provide essential ecosystem services, from carbon sequestration to water regulation, benefiting both local communities and the global climate.
Ensuring that local communities have viable economic alternatives to deforestation and unsustainable land use is essential. Sustainable, well-funded conservation programs must go hand in hand with policies that prevent biodiversity-rich regions from becoming regulatory havens. Investing in these hotspots is not just an ethical responsibility—it is one of the most effective strategies for preserving global biodiversity.
For species like the Crossley’s dwarf lemur, whose survival depends on Madagascar’s rapidly shrinking forests, these efforts are particularly urgent. While this elusive primate persists in several protected areas, habitat loss remains its greatest threat. Without sustained investment in conservation initiatives—such as reforestation efforts, eco-corridors, and community-driven land stewardship—this species, along with many others, risks being pushed toward extinction. Protecting biodiversity hotspots is not just about saving individual species; it is about maintaining the delicate ecological networks that sustain them.
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Written by Zachary Lussier, March 2025