Life expectancy of wild ruminants in zoological institutions.

Vet. med. Diss.
Universität Zürich, Vetsuisse Fakultät.

Volltext: https://www.zora.uzh.ch/id/eprint/54248/1/DM_Dissertation_komplett_110114.pdf

Zusammenfassung:

In der vorliegenden Studie wurden Daten des “International Species Information Systems” verwendet, um die relative Lebenserwartung (rLE;durchschnittliche Lebenserwartung einer Art als Proportion des Altersrekords) von 78 Wiederkäuerartenin Gefangenschaft zu ermitteln. Dieser Wert reflektiert den jeweiligen Haltungserfolg. Die vergleichendeAnalyse der rLE verschiedener Arten ermöglichte es, biologische Merkmale zu identifizieren, die einenEinfluss auf die Lebenserwartung haben. So korrelierte der rLE adulter Weibchen positiv mit dem Anteilan Gras in der natürlichen Äsung einer Art (฀2 = 8.28, p=0.004). Dies bestätigt die Erfahrung aus derZoohaltung, dass Laubäser im Vergleich zu Gras- und Mischäsern mehr fütterungsbedingte Problemezeigen. Höhere rLE erreichten adulte Männchen monogamer Arten (฀2 = 9.92, p=0.007). Dies weistdarauf hin, dass Arten, die daran adaptiert sind, ein Harem oder ein Revier zu verteidigen, intrinsischem,physiologischen Stress ausgesetzt sind, selbst wenn sie nicht in Gesellschaft anderer Männchen gehaltenwerden. Zudem war der rLE beider Geschlechter höher bei Arten, für die ein internationales Zuchtbuchgeführt wird (Weibchen: ฀2 = 8.80, p=0.003, Männchen: ฀2 = 5.52, p=0.019). Dieses Ergebnis zeigt,dass sich ex-situ Zuchtprogramme auch positiv auf den Haltungserfolg einer Art auswirken. Sollten dieErgebnisse dieser Studie in den Haltungsregimen von Wildwiederkäuern berücksichtigt werden, könntederen Haltungserfolg weiter verbessert werden.

müller-biblio

Survival on the ark: life‐history trends in captive parrots.

Animal Conservation 15(1): 28-43. https://doi.org/10.1111/j.1469-1795.2011.00477.x

Volltext: https://zslpublications.onlinelibrary.wiley.com/doi/full/10.1111/j.1469-1795.2011.00477.x

Abstract:

Members of the order Psittaciformes (parrots and cockatoos) are among the most long‐lived and endangered avian species. Comprehensive data on lifespan and breeding are critical to setting conservation priorities, parameterizing population viability models, and managing captive and wild populations. To meet these needs, we analyzed 83 212 life‐history records of captive birds from the International Species Information System (ISIS) and calculated lifespan and breeding parameters for 260 species of parrots (71% of extant species). Species varied widely in lifespan, with larger species generally living longer than smaller ones. The highest maximum lifespan recorded was 92 years in Cacatua moluccensis, but only 11 other species had a maximum lifespan over 50 years. Our data indicate that while some captive individuals are capable of reaching extraordinary ages, median lifespans are generally shorter than widely assumed, albeit with some increase seen in birds presently held in zoos. Species that lived longer and bred later in life tended to be more threatened according to IUCN classifications. We documented several individuals of multiple species that were able to breed for more than two decades, but the majority of clades examined had much shorter active reproduction periods. Post‐breeding periods were surprisingly long and in many cases surpassed the duration of active breeding. Our results demonstrate the value of the ISIS database to estimate life‐history data for an at‐risk taxon that is difficult to study in the wild, and provide life‐history data that is crucial for predictive modeling of future species endangerment and proactively management of captive populations of parrots.

young-biblio

Life expectancy in zoo mammals: what a zoo veterinarian should know.

In: Proceedings of the AAZV Conference, Kansas City, Missouri, USA, 23 Oktober 2011 - 28 Oktober 2011, 181-183.

Volltext

Abstract

Recently several scientific publications have appeared related to the topic of longevity in mammals with a special focus on zoo animals. This presentation summarizes the findings and highlights facts which are of importance for a scientific discussion, especially when data from zoo animals are compared with data from free-ranging conspecifics. Special emphasis is given to the definition of parameters used to quantify longevity, such as survivorship, maximum longevity and mean or relative life expectancy. An above-average life expectancy is considered a sign of successful management of zoo animals, a goal that every modern zoo strives for. Zoos enjoy a public perception that animals in their care have a ―good life free of predators, supported by veterinary care and living longer than their free-living counterparts. This assumption is supported by the fact that longevity records are most often held by zoo animals, which has ironically led to criticism resulting from the problems inherent in an increasing number of geriatric animals. However, scientific analyses of life expectancy in zoo animals, and whether species in zoos generally live longer than their wild counterparts have been sporadic. In several species, it has become apparent that current life expectancies in captivity may indeed be less than those of free-ranging populations. Species investigated include African and Asian elephants (Loxodonta africana and Elephas maximus), roe deer (Capreolus capreolus), moose (Alces alces), orca (Orcinus orca) and walrus (Odobenus rosmarus). Zoo veterinarians are perceived as experts by the general public in evaluating the management of zoo animals and will therefore be answering questions regarding life expectancy in captivity, as well as comparisons to free-ranging conspecifics. It is therefore important that zoo veterinarians are be able to give objective answers regarding life expectancy. It has been hypothesized for several species that reduced longevity is influenced by the captive diet. For Asian elephants, obesity appears to be a problem, and browsing ruminants such as roe deer and moose may not receive adequate fiber sources in captivity. Müller et al. found that the life expectancy of captive female non-domestic ruminants in general correlated with the percentage of grass in a species‘ natural diet, suggesting that the needs of species adapted to grass can be more easily accommodated than those adapted to browse. Another impact on life expectancy is related to reproductive physiology, where captive male non-domestic ruminants of monogamous species demonstrate higher life expectancy than polygamous males, which matches observed differences of sexual bias in life expectancy in free-living populations and thus supports the ecological theory that the mating system influences life expectancy. But it should also be emphasized that Müller et al.  found life expectancy to be higher in non-domestic ruminants managed by international studbooks when compared with species not managed in this way. Results on longevity cannot always be easily compared because different parameters are used. Table 1 summarizes the main parameters that are measured. Studbook data and the International Species Information System (ISIS) represent excellent compilations of data that can be used to investigate longevities for captive animals. Data for wild populations are less available, as many fewer species have been studied in the wild for the long time spans necessary to assemble comprehensive demographic data. In conclusion, there is no doubt that the general assumption that zoo animals live longer than their conspecifics in the wild is not entirely valid, even though studies have involved a limited number of species. It is to be expected that this pattern will continue as additional taxa are analyzed. Certain species represent a challenge for captive management and further research is required. Differences between species may be related to biological adaptations that may directly influence husbandry (such as adaptations to the natural diet), or to biological adaptations in terms of life history, which will not change in captive specimens. These differences are of importance since they emphasize different directions for further investigation. Finally, it should be recognized that longevity is only one of many parameters by which husbandry success can be quantified. High longevities are a side-effect of good husbandry coupled with sufficiently available space for maintaining geriatric animals. A long life as such may, strategically, not be as desirable in itself as a healthy population (and meta-population) with a pyramidal age-structure. However, reduced longevity can serve as an important warning parameter.

hatt-biblio

Longevity of Crocodilians in Captivity.

International Zoo News  Vol. 61. No. 5 (2014), pp. 363-373

Introduction:

Since  1978  the  author  has  collected  numerous  records  on  animal  longevities. This data has been collected during personal examination of archives at zoological collections worldwide and through correspondence with zoo staff members. Taxonomy  in  this  list  follows  that  used  in  the  publications  of  the  Crocodile Specialist Group of the IUCN.

This paper is the first comprehensive listing for every species and subspecies of crocodilian for which the author has a verified and known longevity record, including initial date of entry (hatch, capture, arrival) and a known date of death and/or verification as still living. Documentation of longevities at the subspecies level has  not  been  included  in  previous  treatments  of  the  Crocodilia.  Anecdotal  records  have not been accepted.

weigl-biblio

Comparative analyses of longevity and senescence reveal variable survival benefits of living in zoos across mammals.

Scientific Reports 6, Article number: 36361 (2016)
doi:10.1038/srep36361. http://www.nature.com/articles/srep36361#supplementary-information

Abstract:

While it is commonly believed that animals live longer in zoos than in the wild, this assumption has rarely been tested. We compared four survival metrics (longevity, baseline mortality, onset of senescence and rate of senescence) between both sexes of free-ranging and zoo populations of more than 50 mammal species. We found that mammals from zoo populations generally lived longer than their wild counterparts (84% of species). The effect was most notable in species with a faster pace of life (i.e. a short life span, high reproductive rate and high mortality in the wild) because zoos evidently offer protection against a number of relevant conditions like predation, intraspecific competition and diseases. Species with a slower pace of life (i.e. a long life span, low reproduction rate and low mortality in the wild) benefit less from captivity in terms of longevity; in such species, there is probably less potential for a reduction in mortality. These findings provide a first general explanation about the different magnitude of zoo environment benefits among mammalian species, and thereby highlight the effort that is needed to improve captive conditions for slow-living species that are particularly susceptible to extinction in the wild.

tidiere-biblio

Simultaneous age-dependent and age-independent sexual selection in the lekking black grouse (Lyrurus tetrix).

Journal of Animal Ecology (85): 715–725.

Summary:

1. Individuals’ reproductive success is often strongly associated with their age, with typical patterns of early-life reproductive improvement and late-life senescence. These age-related patterns are due to the inherent trade-offs between life-history traits compet ing for a limited amount of resources available to the organisms. In males, such trade-offs are exacerbated by the resource requirements associated with the expression of costly sexual traits, leading to dynamic changes in trait expression throughout their life span.

2. Due to the age dependency of male phenotypes, the relationship between the expression of male traits and mating success can also vary with male age. Hence, using longitudinal data in a lekking species with strong sexual selection – the black grouse Lyrurus tetrix – we quantified the effects of age, life span and age of first lek attendance (AFL) on male annual mating success (AM S) to separate the effects of within-individual improvement and senescence on AMS from selective (dis)appearance of certain phenotypes. Then, we used male AMS to quantify univariate and multivariate sexual selection gradients on male morphological and behavioural traits with and without accounting for age and age-related effects of other traits.

3. Male AMS increased with age, and there was no significant reproductive senescence. Most males never copulated, and of the ones that did, the majority had onl y one success ful year. Life span was unrelated to AMS, but early AFL tended to lead to higher AMS at ages 1–3. AMS was related to most morphological and behavioural traits when male age was ignored. Accounting for age and age-specific trait effects (i.e. the interaction between a trait and age) reduced the magnitude of the selection gradients and revealed that behavioural traits are under consistent sexual selection, while sexual selection on morphological traits is stronger in old males.

4. Therefore, sexual selection in black grouse operates primarily on male behaviour and morphological traits may act as additional cues to supplement female choice. These results demonstrate the multifaceted influence of age on both fitness and sexual traits and highlight the importance of accounting for such effects when quantifying sexual selection.

kervinen-biblio

Zur Biologie und Evolution der Lebenserwartung von Tieren.

Zool. Garten N.F. 82 (1-2): 72-95.

Abstract:

Biodemography is an emerging field of biology. Zoological Gardens can provide a lot of exact data on mean longevity and maximum life-span. The age of certain animal species are connected with their habitat, their ecology, and the taxonomy. Examples for ages and life-cycles are given for many taxonomic units in this article. The relevance for keeping is discussed. In the focus of the visitor's attention many old animals become “animal personalities”. Such charismatic zoo-animals are often elephants, hippopotamuses, bears or great apes.

ibler-biblio

Estimating bottlenose dolphin population parameters from individual identification and capture-release techniques.

In P. S. Hammond, S. A. Mizroch and G. P. Donovan, eds.: Individual recognition of cetaceans: use of photo-identification and other techniques to estimate population parameters, pp. 407-415.

International Whaling Commission, Cambridge.

wells-biblio

A survival guide to survival rates.

16 Seiten

http://rosmarus.com/Download/Survival.pdf

Introduction

The survival of marine mammals in captivity is often the subject of heated discussions. Interestingly, these discussions usually focus on cetaceans. The discussions are often complicated by a general lack of understanding of the subject matter. This can result in incorrect representation of the available data and comparisons of unrelated parameters. The terminology involved is not straightforward and can be confusing (Fad, 1996). In this paper, I  will discuss the terminology involved, the calculations that must be do ne to derive survival rates and life expectancies and I will look at the presentation of the data and how that can influence the message. A few examples will be given.

toorn-biblio

Zum Lebensalter von Rotduckern (Cephalophus natalensis).

BONGO Berlin 41: 35-38.

rahde-biblio