An official website of the United States government
Introduced predators currently threaten endemic animals on Madagascar through predation, facilitation of human-led hunts, competition, and disease transmission, but the antiquity and past consequences of these introductions are poorly known. We use directly radiocarbon dated bones of introduced dogs ( Canis familiaris ) to test whether dogs could have aided human-led hunts of the island’s extinct megafauna. We compare carbon and nitrogen isotope data from the bone collagen of dogs and endemic “fosa” ( Cryptoprocta spp.) in central and southwestern Madagascar to test for competition between introduced and endemic predators. The distinct isotopic niches of dogs and fosa suggest that any past antagonistic relationship between these predators did not follow from predation or competition for shared prey. Radiocarbon dates confirm that dogs have been present on Madagascar for over a millennium and suggest that they at least briefly co-occurred with the island’s extinct megafauna, which included giant lemurs, elephant birds, and pygmy hippopotamuses. Today, dogs share a mutualism with pastoralists who also occasionally hunt endemic vertebrates, and similar behavior is reflected in deposits at several Malagasy paleontological sites that contain dog and livestock bones along with butchered bones of extinct megafauna and extant lemurs. Dogs on Madagascar have had a wide range of diets during the past millennium, but relatively high stable carbon isotope values suggest few individuals relied primarily on forest bushmeat. Our newly generated data suggest that dogs were part of a suite of animal introductions beginning over a millennium ago that coincided with widespread landscape transformation and megafaunal extinction.
more »
« less
The stories people tell, and how they can contribute to our understanding of megafaunal decline and extinction in Madagascar
Most researchers believe that Madagascar’s megafauna went extinct between 2000 and 1000 years ago. Across Madagascar, fossil specimens of the island’s endemic (and now extinct) pygmy hippopotamuses, elephant birds, giant lemurs, horned crocodiles, and other vertebrates larger in body size than 10 kg commonly date to the first millennium of the Common Era (CE) or earlier; few records date to the second millennium CE. Whereas megafaunal populations appear to have crashed almost simultaneously near the end of the first millennium CE, small populations can survive in remote pockets for centuries after precipitous species decline, perhaps longer. Examining the differences in the population dynamics of declining species and other factors can help to better identify the ultimate timing of extinction. Ever since Etienne de Flacourt traveled to Madagascar in the late 1600s, Malagasy stories of large-bodied wild animals have been recorded. Many include fantastic, clearly mythical creatures, but some provide anatomical or behavioral details which are consistent with legends or even direct observations of real, albeit potentially already extinct, species (including elephant birds, hippopotamuses, and some giant lemurs). In December 1989, at 06:00 hours, one of us (BZF) witnessed a large euplerid carnivoran locally known as fosabe (big fosa) or fosa jobijoby (blackish fosa) who had entered his field tent at Montagne d’Ambre. The animal was “twice the size and much darker than the common fossa” (Freed, 1996, p. 34). The individual was black and weighed approximately 20-25 kg. Freed wrote that the animal was well known to the local people and that “many local people also reported seeing it”. The animal fits paleontologists’ expectations for Cryptoprocta spelea, a large carnivoran known from the fossil record, believed to have been extinct for at least 1000 years. In June 2020, we recorded modern accounts of the big fosa. One of us (ESN) visited villages in four different sectors (Northwest, Northeast, East, and West) of Montagne d’Ambre National Park and the Forêt d’Ambre Special Reserve to examine potential regional differences and/or similarities in the stories of this animal, and whether such accounts include mythical elements, relevant anatomical information, and/or credible recent sightings. We also recorded stories of an Endangered extant animal, the aye-aye of the genus Daubentonia (also known locally as the kakahely). Ultimately, we believe this folklore provides clues that may help elucidate the geography of decline and possible late survival of an “extinct” megafaunal animal on Madagascar.
more »
« less
- Award ID(s):
- 1750598
- PAR ID:
- 10317033
- Date Published:
- Journal Name:
- Malagasy nature
- Volume:
- 15
- ISSN:
- 2661-9032
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Recently expanded estimates for when humans arrived on Madagascar (up to approximately 10 000 years ago) highlight questions about the causes of the island's relatively late megafaunal extinctions (approximately 2000–500 years ago). Introduced domesticated animals could have contributed to extinctions, but the arrival times and past diets of exotic animals are poorly known. To conduct the first explicit test of the potential for competition between introduced livestock and extinct endemic megafauna in southern and western Madagascar, we generated new radiocarbon and stable carbon and nitrogen isotope data from the bone collagen of introduced ungulates (zebu cattle, ovicaprids and bushpigs, n = 66) and endemic megafauna (pygmy hippopotamuses, giant tortoises and elephant birds, n = 68), and combined these data with existing data from endemic megafauna (n = 282, including giant lemurs). Radiocarbon dates confirm that introduced and endemic herbivores briefly overlapped chronologically in this region between 1000 and 800 calibrated years before present (cal BP). Moreover, stable isotope data suggest that goats, tortoises and hippos had broadly similar diets or exploited similar habitats. These data support the potential for both direct and indirect forms of competition between introduced and endemic herbivores. We argue that competition with introduced herbivores, mediated by opportunistic hunting by humans and exacerbated by environmental change, contributed to the late extinction of endemic megafauna on Madagascar.more » « less
-
Madagascar is famous today not only for its unique biodiversity, but also for the high levels of endemism of plants and animals. Less appreciated is the fact that, in the recent past, the island had even greater biodiversity with many other endemic animals such as giant lemurs, elephant birds, pygmy hippopotami, tortoises, and crocodiles that have gone extinct within the past 2000 years. The extinction of many of these groups is thought to be the result of both human activities and environmental change. Most research has focused on the lemurs, hippopotami, and elephant birds. Other recently extinct animals, including the Malagasy horned crocodile (Voay robustus), are relatively poorly known. Madagascar’s subfossil crocodylians include two taxa: the extinct V. robustus (the Malagasy horned crocodile) and the extant Crocodylus niloticus. The latter arrived on Madagascar relatively recently and we know little about the habitat preferences, distributions and ecological interactions (if any) of either species during the Holocene. In order to better understand the recent history of crocodylian extinction in Madagascar, we must first identify which species were present and where they were found. We present here a description of subfossil crocodylian material collected from the newly discovered subfossil site of Tsaramody (Sambaina Basin), a high-elevation wetlandenvironment. At 1655 m, it represents the highest elevation subfossil site on the island. Here we describe both cranial (e.g., premaxillary, jugal, and squamosal “horns”) and postcranial elements (e.g., osteoderms). Our research indicates that crocodile material from Tsaramody appears morphologically to belong to V. robustus, the extinct species. However, oval tuberosities on the frontal bone and a triangular extension of the squamosal bone suggest previously unrecognized variation.more » « less
-
No endemic Madagascar animal with body mass >10 kg survived a relatively recent wave of extinction on the island. From morphological and isotopic analyses of skeletal “subfossil” remains we can reconstruct some of the biology and behavioral ecology of giant lemurs (primates; up to ∼160 kg) and other extraordinary Malagasy megafauna that survived into the past millennium. Yet, much about the evolutionary biology of these now-extinct species remains unknown, along with persistent phylogenetic uncertainty in some cases. Thankfully, despite the challenges of DNA preservation in tropical and subtropical environments, technical advances have enabled the recovery of ancient DNA from some Malagasy subfossil specimens. Here, we present a nuclear genome sequence (∼2× coverage) for one of the largest extinct lemurs, the koala lemur Megaladapis edwardsi (∼85 kg). To support the testing of key phylogenetic and evolutionary hypotheses, we also generated high-coverage nuclear genomes for two extant lemurs, Eulemur rufifrons and Lepilemur mustelinus , and we aligned these sequences with previously published genomes for three other extant lemurs and 47 nonlemur vertebrates. Our phylogenetic results confirm that Megaladapis is most closely related to the extant Lemuridae (typified in our analysis by E. rufifrons ) to the exclusion of L. mustelinus , which contradicts morphology-based phylogenies. Our evolutionary analyses identified significant convergent evolution between M. edwardsi and an extant folivore (a colobine monkey) and an herbivore (horse) in genes encoding proteins that function in plant toxin biodegradation and nutrient absorption. These results suggest that koala lemurs were highly adapted to a leaf-based diet, which may also explain their convergent craniodental morphology with the small-bodied folivore Lepilemur .more » « less
-
NA (Ed.)Madagascar, an island renowned for its rich biodiversity, is home to an impressive variety of bird species. The island’s Quaternary subfossil sites have yielded the remains of birds that bear testimony to an even richer avifauna during the recent past (Figure 1). These species are also excellent indicators of past habitats, due to habitat-specific adaptations (Behrensmeyer et al., 2003; Carrera et al., 2021). We studied the subfossil avifauna from Vintany Cave at Tsimanampesotse, SW Madagascar, to reconstruct the habitats of this region prior to human population expansion. The bird fossils were found in deposits alongside remains of other vertebrate species including large-bodied frugivorous lemurs, browsing elephant birds, and carnivorans such as Fossa fossana and Cryptoprocta spelea, the latter an extinct euplerid that preyed on large- bodied lemurs such as Pachylemur and Megaladapis. Radiocarbon dates establish an age range between 2000 and 3000 yr BP.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- The DOI is not currently available.
