Alligators as Predators on Terrestrial Mammals

Shoop, C. Robert; Ruckdeschel, Carol

doi:10.2307/2426191

Cited by 32 publications

(18 citation statements)

References 11 publications

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“…In fact, alligators are opportunistic omnivores that feed on a variety of aquatic, semiaquatic, and terrestrial prey (Delany and Abercrombie, 1986;Shoop and Ruckdeschel, 1990). Their relatively low trophic position could be the result of several factors.…”

Section: Discussionmentioning

confidence: 99%

“…First, a significant portion of their energy may be derived directly from primary consumers such as crayfish or snails. Second, a significant proportion of the alligator diet may be from the terrestrial food web (i.e., birds, mammals, terrestrial-feeding amphibians), which have lower baseline d 15 N values as compared to aquatic food webs (Shoop and Ruckdeschel, 1990). Third, they may frequently ingest large amounts of detritus incidentally while foraging.…”

Section: Discussionmentioning

confidence: 99%

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Trophic Interactions of Turtles in a North Florida Lake Food Web: Prevalence of Omnivory

Aresco

Travis

Macrae

2015

Copeia

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Omnivory is ubiquitous in aquatic and terrestrial ecosystems and may increase stability of food webs. Turtles are longlived and among the most abundant organisms in lentic aquatic habitats. Many species are omnivores and thus may be especially important in regulating ecosystem dynamics in these systems. Turtles are also one of the most threatened vertebrate groups in the world; if they indeed play pivotal roles in lentic ecosystems, their declines may disrupt or even destabilize those ecosystems. In order to assess the role of turtles in an aquatic ecosystem, we examined sources of primary production, trophic structure, and ontogenetic diet shifts of five species of turtles, other herpetofauna, and fish in a large shallow lake in northern Florida. Stable isotope analyses (d 13 C and d 15 N) of 42 species of animals and five sources of primary productivity revealed that macroalgae and/or particulate organic matter were the foundation of the food web. Trophic structure of the herpetofauna and fish indicated a high degree of omnivory (TPs of 3-4), few specialists at high trophic levels (TP $ 4.0), and few strict primary consumers (TP = 2.0). Several predatory fish (Micropterus salmoides, Lepomis gulosus, and Pomoxis nigromaculatus) and herpetological predators (e.g., Alligator, Nerodia) were functionally trophic omnivores with trophic positions lowered by predation on primary and low trophic position secondary consumers. We found two major divisions in the trophic structure of turtles-an herbivore (Pseudemys floridana) and four omnivores (Apalone ferox, Chelydra serpentina, Sternotherus odoratus, and Trachemys scripta). There were at least three types of omnivores, species that are generalist feeders throughout their life (e.g., C. serpentina, S. odoratus), species that change their trophic position during ontogeny (e.g., A. ferox), and species with the same trophic position through ontogeny but resulting from different diet composition as juveniles and adults (e.g., T. scripta). Trophic position of some species indicated that even when turtles are primarily predatory, they also function as vegetative consumers and facultative scavengers (e.g., T. scripta, S. odoratus, A. ferox). Given that omnivory is a critical process that can stabilize food webs, there will certainly be dramatic shifts in how energy and nutrients flow through these lentic ecosystems if turtle populations decline.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Trophic Interactions of Turtles in a North Florida Lake Food Web: Prevalence of Omnivory

Aresco

Travis

Macrae

2015

Copeia

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“…While predation seems to be an important source of armadillo mortality at our study site, it is unclear what is preying on them. Known predators of armadillos in the United States include puma, Feiis concolor (Carr, 1982;Maehr et ai., 1990), American black bear, Ursus americanus (Harlow, 1961;Maehr and Brady, 1982) and the American alligator, Alligator mississippiensis (McNease and loanen, 1977;Shoop and Ruckdeschel, 1990). However, except for alligators, these species are either rare or absent on the refuge, and alligators presumably would not leave carapace remains on land.…”

Section: Discussionmentioning

confidence: 99%

“…Adult mortality was rarer than juvenile mortality. Adults have been reported killed by many of the species mentioned above (Harlow, 1961;McNease and loanen, 1977;Carr, 1982;Maehr and Brady, 1982;Shoop and Brady, 1982;Maehr et ai., 1990;Shoop and Ruckdeschel, 1990), but it seems likely that they are taken less often as prey than are juveniles, presumably because adults are larger and have more experience at avoiding predators. Indeed, in the present study we found no evidence of predation on any of the adult carapaces we examined.…”

Section: Discussionmentioning

confidence: 99%

Patterns of Mortality in a Population of Nine-banded Armadillos, Dasypus novemcinctus

McDonough¹,

Loughry²

1997

American Midland Naturalist

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Weused data from carcasses found in a natural population of nine-banded armadillos (Dasypus novemcinctus) to assess the sources and age structure of mortality. Juveniles (young of the year) made up approximately 33% of the living population, but constituted about 60% of all carapaces collected. Circumstantial evidence indicated that most juvenile, but not adult, mortality was probably due to predation. Increased adult mortality was associated with a period of prolonged drought.

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“…Tooth shape may indicate differences in feeding behavior and processing ability, even though overlap exists in prey selection. Alligator mississippiensis and Crocodilus niloticus both consume a wide variety of prey, including both large and small mammals, crustaceans, fish, water fowl, snakes, turtles, and conspecifics (McIlenny, 1976;Pooley & Gans, 1976;Groombridge, 1982;Delany and Abercrombie, 1986;Hutton, 1987;Shoop & Ruckdeschel, 1990; PeerJ reviewing PDF | (2018:07:29741:3:0:NEW 17 Jan 2019)…”

Section: Members Of Alligator Sinensis Differed From This Though In mentioning

confidence: 99%

Peer Review #3 of "Quantitative heterodonty in Crocodylia: assessing size and shape across modern and extinct taxa (v0.2)"

Cossette¹

2019

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Heterodonty in Crocodylia and closely related taxa has not been defined quantitatively, as the teeth rarely have been measured. This has resulted in a range of qualitative descriptors, with little consensus on the condition of dental morphology in the clade. The purpose of this study is to present a method for the quantification of both size-and shapeheterodonty in members of Crocodylia. Data were collected from dry skeletal and fossil specimens of 34 crown crocodylians and one crocodyliform, resulting in 21 species total. Digital photographs were taken of each tooth and the skull, and the margins of both were converted into landmarks and semilandmarks. We expressed heterodonty through Foote's morphological disparity, and a principal components analysis quantified shape variance. All specimens sampled were heterodont to varying degrees, with the majority of the shape variance represented by a 'caniniform' to 'molariform' transition. Heterodonty varied significantly between positions; size undulated whereas shape was significantly linear from mesial to distal. Size and shape appeared to be primarily decoupled. Skull shape correlated significantly with tooth shape. High size-heterodonty often correlated with very large caniniform teeth, reflecting a prioritization of securing prey. Large, highly molariform, distal teeth may be a consequence of high-frequency durophagy combined with prey size. The slender-snouted skull shape correlated with a caniniform arcade with low heterodonty. This was reminiscent of other underwater-feeding tetrapods, as they often focus on small prey that requires minimal processing. Several extinct taxa were very molariform, which was associated with low heterodonty. The terrestrial peirosaurid shared similarities with large modern crocodylian taxa, but may have processed prey differently. Disparity measures can be inflated or deflated if certain teeth are absent from the tooth row, and regression analysis may not best apply to strongly slender-snouted taxa. Nevertheless, when these methods are used in tandem they can give a complete picture of crocodylian heterodonty. Future researchers may apply our proposed method to most crocodylian

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Alligators as Predators on Terrestrial Mammals

Cited by 32 publications

References 11 publications

Trophic Interactions of Turtles in a North Florida Lake Food Web: Prevalence of Omnivory

Trophic Interactions of Turtles in a North Florida Lake Food Web: Prevalence of Omnivory

Patterns of Mortality in a Population of Nine-banded Armadillos, Dasypus novemcinctus

Peer Review #3 of "Quantitative heterodonty in Crocodylia: assessing size and shape across modern and extinct taxa (v0.2)"

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