The role of forage availability on diet choice and body condition in American beavers (Castor canadensis)

Abstract:Lizards of the genusAnolishave been widely studied, however, little is known about the effects of environmental seasonality, food availability and geographic isolation on body condition, growth rate and habitat use of lizards. The existence of an insular and a continental population ofAnolis nebulosus(clouded anole), separated by only 0.47 km, represents an ideal opportunity to address this topic. We compared seasonal fluctuations in food availability (arthropod density) for anoles, as well as body condition, growth rate and habitat use in the two populations. Food availability throughout the year was sampled every 2 mo by trapping arthropods at each site. Lizards were also monitored and measured every 2 mo by surveying three quadrats in each site over 2 y giving a total of 30 visits for each quadrat. Results suggested that composition and density of food supply was similar for the two populations. Nevertheless, food supply responded to seasonality of rainfall, with an increase of 1.5 times during the rainy season. Despite similarity in food availability, insular anoles had body condition that was 5–10 times better, with growth rate twice as fast, and used similar perches. The role of predation, and inter- and intraspecific competition are discussed as possible drivers.

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Conservation of erupting ungulate populations on islands – a comment

Rangifer ◽

10.7557/2.23.2.361 ◽

2003 ◽

Vol 23 (2) ◽

pp. 57 ◽

Cited By ~ 2

Author(s):

Anne Gunn ◽

Frank L. Miller ◽

Samuel J. Barry

Keyword(s):

Density Dependence ◽

Rangifer Tarandus ◽

Abiotic Factors ◽

Environmental Variation ◽

Juvenile Survival ◽

Relative Importance ◽

Subsequent Performance ◽

Forage Availability ◽

Over Time

A generalised model for herbivores experiencing abundant forage over time is that their numbers erupt and then decline. This model has been applied to fluctuations in caribou (Rangifer tarandus) populations especially those on islands. Since this generalised model for erupting herbivores was first proposed, two assumptions have slipped in (1) that an erupting population will crash; and (2) that the crash will be density-dependent. The problem with the assumptions is that, without testing, they can lead to inappropriate management such as culls. The first assumption arises from uncritical use of earlier accounts and the second assumption from not discriminating between the effects of environmental variation from the effects of the high herbivore numbers on forage availability (density-dependence). Often typical densitydependent effects such as lowered initial reproduction, reduced early survival of calves, and subsequent calf, yearling and juvenile survival are used to justify the contention that there are too many herbivores. But such reasoning is flawed unless cause/effect relationships are established and the role of environmental variation is evaluated. We argue that it is overly simplistic to believe that every population’s subsequent performance and fate will follow a singular pattern with only one paramount factor driving and ultimately dictating an inevitable outcome. The relative importance of unpredictable abiotic factors in influencing and causing variation in the response of ungulate populations should be investigated, no matter whether those factors are sporadic or periodic.

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Dentition and body condition: tooth wear as a correlate of weight loss in roe deer

Frontiers in Zoology ◽

10.1186/s12983-021-00433-w ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Roberta Chirichella ◽

Anna Maria De Marinis ◽

Boštjan Pokorny ◽

Marco Apollonio

Keyword(s):

Body Mass ◽

Body Condition ◽

Physical Condition ◽

Roe Deer ◽

Tooth Wear ◽

The Body ◽

Permanent Teeth ◽

Tooth Surface ◽

Mandible Length

Abstract Background In many mammalian species, once the permanent teeth have erupted, the only change to dentition is a gradual loss of tooth surface/height through wear. The crown of the teeth cannot be repaired once worn. When dental crown tissue has been depleted due to wear, the animal is expected to have a suboptimal body condition. We evaluated the role of tooth wear in causing a reduction of physical condition in adult roe deer females (Capreolus capreolus). Results The progressive wearing of the lower cheek teeth was assessed in a Northern Apennines (Italy) population with a new scoring scheme based on objectively described tooth characteristics (morphotypes) being either present or absent. Eviscerated body mass and mandible length, which is a good proxy for body size in roe deer, were related to the tooth wear score by the use of linear regressions. The sum of wear scores for molariform teeth correlated most strongly with body condition (i.e., eviscerated body mass/mandible length), showing the importance of the entire chewing surface for acquiring energy by food comminution, chewing, and digestion. In comparison with individuals of comparable size experiencing minor tooth wear, the body mass of those with the most advanced stage of tooth wear was decreased by 33.7%. This method was compared to the height and the hypsodonty index of the first molar, the most commonly used indices of tooth wear. The sum of molariform wear scoring scheme resulted in a more suitable index to describe the variation in body condition of roe deer. Conclusions Describing tooth wear patterns in hunted populations and monitoring at which tooth wear level (and therefore dental morphotype) an animal is no longer able to sustain its physical condition (i.e. when it begins to lose body mass) can be a useful tool for improving the management of the most widespread and abundant deer species in Europe. At the same time, such an approach can clarify the role of tooth wear as a proximate cause of senescence in ungulates.

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Review for "Role of body condition score and adiponectin expression in the progression of canine mammary carcinomas"

10.1002/vms3.238/v1/review1 ◽

2019 ◽

Author(s):

A. F. Coleto

Keyword(s):

Body Condition ◽

Body Condition Score ◽

Mammary Carcinomas ◽

Condition Score

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Equine obesity and the role of the veterinary nurse

UK-Vet Equine ◽

10.12968/ukve.2021.5.6.265 ◽

2021 ◽

Vol 5 (6) ◽

pp. 265-268

Author(s):

Clarissa Seeley ◽

Stella Chapman

Keyword(s):

Body Condition ◽

The Body ◽

Body Condition Scoring ◽

Client Education ◽

Inherent Problem ◽

Equine Obesity ◽

The Individual ◽

The Uk

Equine obesity is defined as a medical disease in which excess body fat has accumulated to such an extent that it has an adverse effect on the general health of the horse. Obesity is a cause for concern, with one-third of the equine population in the UK being regarded as obese, although owner recognition of obesity in horses is an inherent problem, with many underestimating the body condition or weight of their horse. This is further complicated by the fact that with larger framed horses, or horses that are already overweight, assessing body condition is more difficult. There are a number of ways to assess body condition and the most practical means of regular assessment is body condition scoring, although this is regarded as subjective. As with many diseases and disorders, the cause of obesity is multifactorial. However, the most common reason for a horse to become obese is overfeeding, coupled with a lack of exercise. Obesity can be addressed with client education and veterinary nurses can provide advice on weight management programmes. However, these need to be tailored to the individual horse and owners need to recognise that they are entering into a long-term commitment.

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