The huemul (Hippocamelus bisulcus) is endangered, with 1500 deer split into >100 subpopulations along 2000 km of the Andes. Currently occupied areas are claimed-erroneously-to be critical prime habitats. We analyzed historical spatiotemporal behavior since current patterns represent only a fraction of pre-Columbian ones. Given the limited knowledge, the first group (n = 6) in Argentina was radio-marked to examine spatial behavior. Historically, huemul resided year-round in winter ranges, while some migrated seasonally, some using grasslands >200 km east of their current presence, reaching the Atlantic. Moreover, huemul anatomy is adapted to open unforested habitats, also corroborated by spotless fawns. Extreme naivety towards humans resulted in early extirpation on many winter ranges—preferentially occupied by humans, resulting in refugee huemul on surrounding mountain summer ranges. Radio-marked huemul remained in small ranges with minimal altitudinal movements, as known from other subpopulations. However, these resident areas documented here are typical summer ranges as evidenced by past migrations, and current usage for livestock. The huemul is the only cervid known to use mountain summer ranges year-round in reaction to anthropogenic activities. Losing migratory traditions is a major threat, and may explain their presently prevalent skeletal diseases, reduced longevity, and lacking recolonizations for most remaining huemul subpopulations.

The last 1500 endangered Patagonian huemul deer (Hippocamelus bisulcus) exist in > 100 groups which are not recovering. Prevalence of osteopathology in dead huemul was 57+% (Argentina), whereas similar cases in Chile were accompanied by selenium deficiency. The first clinical cases from live wild huemul confirm widespread osteopathology which explains short life spans, low recruitment, and thus absence of population recovery. The first-ever radio-collaring of 3 male huemul in Argentina and 3 females, plus a fresh female carcass allowed examination of 7 huemul. Of these, 86% were diseased and clinical pathophysiognomy included lameness, affected hoof, exfoliation of 2–7 incisors, other cranial osteopathologies, and muscle atrophy. The parsimonious explanation for absent population recovery is high prevalence of osteopathology as evidenced earlier in carcasses, and now by these clinical cases. Areas currently used by huemul have reduced selenium bioavailability, very deficient soil levels, and overt selenium deficiency in local livestock and plants. These areas are known to result in primary iodine deficiency which is aggravated by selenium deficiency. The nexus to nutritional ecology of huemul likely is inaccessibility to most fertile lowlands and traditional winter ranges, elimination of migratory traditions, and concomitant elimination of source populations.

Huemul (Hippocamelus bisulcus) is a native deer of Patagonia whose endangered status has raised concerns for several decades, and yet conservation efforts to reverse this situation have not succeeded for most populations. Captive breeding projects attempted in the past were short-lived; animals were often lost due to poor methodology or unsanitary conditions during capture, transport stresses and rudimentary husbandry, and reintroductions could not be realised. Despite inappropriate capture and transport techniques of the past, a few individuals did make it to captive centres where they managed to survive for several years, with a minimum of eight births recorded. Regardless of the successes, it is the past failures that impinge upon today’s conservation efforts. In Argentina, a recent financially backed proposal – establishing a huemul breeding centre and including an in situ reintroduction program – was prevented by the prevailing opinion that captive breeding was neither feasible nor a necessary conservation tool for huemul. In Chile, the Huilo Huilo Foundation was able to obtain government consent and to establish the only captive breeding project in the last two decades with the main objective of reintroducing individuals in the future. Here we present some of the historical accounts to demonstrate the suitability of the species to captivity. We then describe the Chilean semi-captive breeding program (begun in 2005) including capture, transport, site selection, construction design and maintenance procedures of the two centres. The first centre has grown from an initial two adults to nine individuals. The second centre, which initially served for rehabilitation of an injured male, is awaiting arrival of some females. The success of the current program demonstrates that huemul can do well in captivity, and wherever considered beneficial, could serve as a significant conservation tool for the recovery of the species, inclusive of a research program and reintroductions to qualified sites.

A symposium was held for the two South American deer of the genus Hippocamelus: the taruka, H. antisensis and the Patagonian huemul, H. bisulcus. The taruka is recognized as vulnerable and the huemul as endangered on the IUCN red list. To reverse the current trend and prevent further imminent declines, 13 recommendations were proposed. For taruka, national recovery plans should be developed and implemented in each country it inhabits, and hunting must be managed. For huemul’s lack of recovery, much still remains unknown about the causal factors and their overall significance: culpeo fox (Pseudalopex culpaeus) appear not to be an important mortality agent of heumul fawns, whereas habitat suitability may be the fundamental cause for the declines. Research should be conducted to better evaluate the interplay of threats and their relative importance.

Conservation strategies for huemul (Hippocamelus bisulcus), listed as an endangered cervid by IUCN, have not helped to reverse its declining population trends. Recent evaluations of historical data revealed that they also inhabited lower valleys and grasslands as residents or only during winter. However, the dogma persists that huemuls do not need such habitats. To determine if more solid evidence exists to back up or refute our hypothesis that huemuls once inhabited lower valleys and grasslands, we researched the literature and discovered additional relevant historical sources on this species. These new findings substantiate that huemuls also occupied unforested areas, reaching the Atlantic coast, and resided on various islands including Tierra del Fuego, and that their co-occurrence with guanaco was frequent. Their extreme naivety towards humans resulted in their extirpation on winter ranges settled by humans, resulting in refugee huemuls year-round on remote mountain summer ranges. The ease by which indigenous people could kill them for subsistence and commercial export of hides to Europe, followed by the lowlands becoming modified by settlers and their exotic species facilitated the huemuls’ extirpation. The hypothesis of a dramatic modification of the original biogeographical distribution of huemuls is supported by anatomical and ecological features along with historical accounts. Sedentariness on only rugged summer ranges makes long-term survival of this species crucially challenging and requires sound conservation strategies that incorporate geographical areas of their former distribution.

Pudu (Pudu puda), occurring in the southern cone of Latin America, has been classified as vulnerable by the International Union for Conservation of Nature (IUCN), yet little is known about this animal in the wild, with most knowledge on the breeding behaviour coming from captive animals. For this second-smallest deer in the world, delayed implantation has been suggested to explain the two peaks in the annual cycle of male sexual hormones on the basis of the accepted tenet that the breeding period occurs only once a year, between March and June. However, in the present study, birth dates from fawns born at the Los Canelos semi-captive breeding centre in Chile and male courting behaviour revealed the possibility of two rutting periods: autumn and spring. To our knowledge, this is the first time that late-fall births (May through early June for 17% of fawns in the study population) have been recorded for the southern pudu; two of these four births were conceived by females in the wild. From zoo and captive-animal birth records (n = 97), only three fawns were born in the fall. For all births combined (n = 121), 77% occurred in spring. The roe deer (Capreolus capreolus) and Pere David deer (Elaphurus davidianus) have been considered the only two temperate cervids in which sexual activity is initiated by increasing daylength and which breed in early summer. Yet, the present results indicate a similar response from the southern pudu when under a wild or semi-captive environment, with breeding taking place in spring. These results suggest that this species may either have two reproductive periods per year or retains the capacity to be a breeder for a much more extended period of time than documented by earlier studies. Pudu, like other temperate deer, is responsive to photoperiod for timing its breeding period, but may further optimise its production of offspring by also responding to other environmental cues such as seasonal variation in food supply when climatic conditions are favourable.