. 2023 Oct 25;290(2009):20231895.

doi: 10.1098/rspb.2023.1895. Epub 2023 Oct 18.

Survival improvements of marine mammals in zoological institutions mirror historical advances in human longevity

Morgane Tidière^{1

2

3}, Fernando Colchero^{1

4

5}, Johanna Staerk^{1

2

3}, Michael J Adkesson⁶, Ditte H Andersen², Lucie Bland^{3

7}, Martin Böye⁸, Sabrina Brando⁹, Isabella Clegg¹⁰, Sarah Cubaynes¹¹, Amy Cutting¹², Danny De Man¹³, Andrew E Derocher¹⁴, Candice Dorsey¹⁵, William Elgar¹⁶, Eric Gaglione¹⁷, Kirstin Anderson Hansen^{2

18}, Allison Jungheim¹⁹, José Kok²⁰, Gail Laule²¹, Agustín Lopez Goya²², Lance Miller⁶, Tania Monreal-Pawlowsky²³, Katelyn Mucha³, Megan A Owen²⁴, Stephen D Petersen²⁵, Nicholas Pilfold²⁴, Douglas Richardson^{26

27}, Evan S Richardson²⁸, Devon Sabo²⁹, Nobutaka Sato³⁰, Wynona Shellabarger³¹, Cecilie R Skovlund^{32

33}, Kanako Tomisawa³⁴, Sandra E Trautwein³, William Van Bonn³⁵, Cornelis Van Elk³⁶, Lorenzo Von Fersen³⁷, Magnus Wahlberg^{2

18}, Peijun Zhang³⁸, Xianfeng Zhang³⁹, Dalia A Conde^{1

2}

Affiliations

¹ Interdisciplinary Centre on Population Dynamics (CPop), University of Southern Denmark, Odense, Denmark.
² Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark.
³ Conservation and Science Department, Species360, 7900 International Drive, Suite 300, Minneapolis, MN 55425, USA.
⁴ Department of Mathematics and Computer Science, University of Southern Denmark, Odense, Denmark.
⁵ Department of Primate Behavior and Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Pl. 6, 04103 Leipzig, Germany.
⁶ Chicago Zoological Society, Brookfield Zoo, Brookfield, IL, USA.
⁷ Eureka Publishing, Thornbury, Australia.
⁸ Centre de Recherche et d'Etude pour l'Animal Sauvage, Planète Sauvage, 44710 Port Saint Pere, France.
⁹ AnimalConcepts, PO Box 378, 03725 Teulada, Alicante, Spain.
¹⁰ Animal Welfare Expertise, The Knoll, Woodlands, Combe Martin, EX34 0ATLittleton Manor, Winchester SO22 6QU, UK.
¹¹ CEFE, Univ Montpellier, CNRS, EPHE-PSL University, IRD, Montpellier, France.
¹² Polar Bear International, PO Box 3008, Bozeman, MT, USA.
¹³ European Association of Zoos and Aquaria (EAZA), Plantage Middelaan 45, 1018-DC Amsterdam, The Netherlands.
¹⁴ Department of Biological Sciences, University of Alberta; Edmonton, Alberta, Canada T6G 2E9.
¹⁵ Association of Zoos and Aquariums, 8403 Colesville Road Ste 710, Silver Spring, MD 20910, USA.
¹⁶ Zoo Miami, 12400 SW 152 Street, Miami, FL 33177, USA.
¹⁷ Georgia Aquarium, 225 Baker Street, Atlanta, GA 30313, USA.
¹⁸ Marine Biological Research Center, University of Southern Denmark, Hindsholmvej 11, 5300 Kerteminde, Denmark.
¹⁹ Como Park Zoo and Conservatory, 1225 Estabrook Dr., Saint Paul, MN 55103, USA.
²⁰ Ouwehands Zoo, Grebbeweg 111, 3911 AV Rhenen, The Netherlands.
²¹ Mandai Wildlife Group, 80 Mandai Lake Road, Singapore 729826.
²² Zoo Aquarium de Madrid, Casa de Campo s/n, 28011 Madrid, Spain.
²³ International Zoo Veterinary Group, Keighley, UK.
²⁴ San Diego Zoo Wildlife Alliance, 15600 San Pasqual Valley Rd., Escondido, CA, USA.
²⁵ Assiniboine Park Zoo, Winnipeg, Manitoba, Canada.
²⁶ Zoological Consultancy Ltd, Columba Cottage, Mill Rd, Kingussie PH21 1LF, UK.
²⁷ EAZA Polar Bear EEP, Amsterdam, Netherlands.
²⁸ Environment and Climate Change Canada, Unit 150-234 Donald Street, Winnipeg, Manitoba R3C 1M8, Canada.
²⁹ Columbus Zoo and Aquarium, 4850 W. Powell Road, PO Box 400, Powell, OH 43065-0400, USA.
³⁰ Asahiyama Zoological Park, Kuranuma, Higasiasahikawacho, Asahikawa city, Japan.
³¹ Detroit Zoological Society, 8450 W. 10 Mile Rd, Royal Oak, MI 48067, USA.
³² Conservation, Copenhagen Zoo, Roskildevej 38, 2000 Frederiksberg, Denmark.
³³ Section of Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, University of Copenhagen, Grønnegårdsvej 8, 1870 Frederiksberg, Denmark.
³⁴ Omuta City Zoo, 163 Showa-machi, Omuta, Fukuoka 836-0871, Japan.
³⁵ A. Watson Armour III, Center for Animal Health and Welfare, Animal Care and Science Division, John G. Shedd Aquarium, Chicago, IL 60605, USA.
³⁶ Independent practitioner, Arendsweg 98, Enschede 7544RM, The Netherlands.
³⁷ Nuremberg Zoo, Am Tiergarten 30, 90480 Nuremberg, Germany.
³⁸ Mammal and Marine Bioacoustics Laboratory Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, People's Republic of China.
³⁹ Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, People's Republic of China.

PMID: 37848064
PMCID: PMC10581765
DOI: 10.1098/rspb.2023.1895

Survival improvements of marine mammals in zoological institutions mirror historical advances in human longevity

Morgane Tidière et al. Proc Biol Sci. 2023.

. 2023 Oct 25;290(2009):20231895.

doi: 10.1098/rspb.2023.1895. Epub 2023 Oct 18.

Authors

Affiliations

¹ Interdisciplinary Centre on Population Dynamics (CPop), University of Southern Denmark, Odense, Denmark.
² Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark.
³ Conservation and Science Department, Species360, 7900 International Drive, Suite 300, Minneapolis, MN 55425, USA.
⁴ Department of Mathematics and Computer Science, University of Southern Denmark, Odense, Denmark.
⁵ Department of Primate Behavior and Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Pl. 6, 04103 Leipzig, Germany.
⁶ Chicago Zoological Society, Brookfield Zoo, Brookfield, IL, USA.
⁷ Eureka Publishing, Thornbury, Australia.
⁸ Centre de Recherche et d'Etude pour l'Animal Sauvage, Planète Sauvage, 44710 Port Saint Pere, France.
⁹ AnimalConcepts, PO Box 378, 03725 Teulada, Alicante, Spain.
¹⁰ Animal Welfare Expertise, The Knoll, Woodlands, Combe Martin, EX34 0ATLittleton Manor, Winchester SO22 6QU, UK.
¹¹ CEFE, Univ Montpellier, CNRS, EPHE-PSL University, IRD, Montpellier, France.
¹² Polar Bear International, PO Box 3008, Bozeman, MT, USA.
¹³ European Association of Zoos and Aquaria (EAZA), Plantage Middelaan 45, 1018-DC Amsterdam, The Netherlands.
¹⁴ Department of Biological Sciences, University of Alberta; Edmonton, Alberta, Canada T6G 2E9.
¹⁵ Association of Zoos and Aquariums, 8403 Colesville Road Ste 710, Silver Spring, MD 20910, USA.
¹⁶ Zoo Miami, 12400 SW 152 Street, Miami, FL 33177, USA.
¹⁷ Georgia Aquarium, 225 Baker Street, Atlanta, GA 30313, USA.
¹⁸ Marine Biological Research Center, University of Southern Denmark, Hindsholmvej 11, 5300 Kerteminde, Denmark.
¹⁹ Como Park Zoo and Conservatory, 1225 Estabrook Dr., Saint Paul, MN 55103, USA.
²⁰ Ouwehands Zoo, Grebbeweg 111, 3911 AV Rhenen, The Netherlands.
²¹ Mandai Wildlife Group, 80 Mandai Lake Road, Singapore 729826.
²² Zoo Aquarium de Madrid, Casa de Campo s/n, 28011 Madrid, Spain.
²³ International Zoo Veterinary Group, Keighley, UK.
²⁴ San Diego Zoo Wildlife Alliance, 15600 San Pasqual Valley Rd., Escondido, CA, USA.
²⁵ Assiniboine Park Zoo, Winnipeg, Manitoba, Canada.
²⁶ Zoological Consultancy Ltd, Columba Cottage, Mill Rd, Kingussie PH21 1LF, UK.
²⁷ EAZA Polar Bear EEP, Amsterdam, Netherlands.
²⁸ Environment and Climate Change Canada, Unit 150-234 Donald Street, Winnipeg, Manitoba R3C 1M8, Canada.
²⁹ Columbus Zoo and Aquarium, 4850 W. Powell Road, PO Box 400, Powell, OH 43065-0400, USA.
³⁰ Asahiyama Zoological Park, Kuranuma, Higasiasahikawacho, Asahikawa city, Japan.
³¹ Detroit Zoological Society, 8450 W. 10 Mile Rd, Royal Oak, MI 48067, USA.
³² Conservation, Copenhagen Zoo, Roskildevej 38, 2000 Frederiksberg, Denmark.
³³ Section of Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, University of Copenhagen, Grønnegårdsvej 8, 1870 Frederiksberg, Denmark.
³⁴ Omuta City Zoo, 163 Showa-machi, Omuta, Fukuoka 836-0871, Japan.
³⁵ A. Watson Armour III, Center for Animal Health and Welfare, Animal Care and Science Division, John G. Shedd Aquarium, Chicago, IL 60605, USA.
³⁶ Independent practitioner, Arendsweg 98, Enschede 7544RM, The Netherlands.
³⁷ Nuremberg Zoo, Am Tiergarten 30, 90480 Nuremberg, Germany.
³⁸ Mammal and Marine Bioacoustics Laboratory Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, People's Republic of China.
³⁹ Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, People's Republic of China.

PMID: 37848064
PMCID: PMC10581765
DOI: 10.1098/rspb.2023.1895

Abstract

An intense public debate has fuelled governmental bans on marine mammals held in zoological institutions. The debate rests on the assumption that survival in zoological institutions has been and remains lower than in the wild, albeit the scientific evidence in support of this notion is equivocal. Here, we used statistical methods previously applied to assess historical improvements in human lifespan and data on 8864 individuals of four marine mammal species (harbour seal, Phoca vitulina; California sea lion, Zalophus californianus; polar bear, Ursus maritimus; common bottlenose dolphin, Tursiops truncatus) held in zoos from 1829 to 2020. We found that life expectancy increased up to 3.40 times, and first-year mortality declined up to 31%, during the last century in zoos. Moreover, the life expectancy of animals in zoos is currently 1.65-3.55 times longer than their wild counterparts. Like humans, these improvements have occurred concurrently with advances in management practices, crucial for population welfare. Science-based decisions will help effective legislative changes and ensure better implementation of animal care.

Keywords: adult mortality; first-year mortality; life expectancy; lifespan equality; population welfare.

PubMed Disclaimer

Conflict of interest statement

In accordance with our ethical obligations as researchers, we hereby disclose that the Species360 Conservation Science Alliance received funding from our Species360 members, which share their data by means of the Species360 ZIMS. Our members include over 1300 zoos, aquariums, rescue centres, sanctuaries and other worldwide wildlife organizations that believe in sharing standardized records of more than 22 000 species through ZIMS. One of the main aims of data standards and sharing is to obtain sufficient sample sizes to develop research and analytics to support evidence-based decisions on animal care and species conservation. In addition, 25 co-authors work in zoological or aquarium organizations, including non-Species360 members.

Figures

**Figure 1.**
Distribution of ages at death (i.e. proportion of individuals dying at each age) by period for both sexes of zoo-held harbour seal (*Phoca vitulina*), California sea lion (*Zalophus californianus*), polar bear (*Ursus maritimus*) and common bottlenose dolphin (*Tursiops truncatus*) obtained from the output of the Bayesian survival trajectory analyses. Inset pie charts show the percentage of first-year mortality. See electronic supplementary material, table S1 for sample sizes. Silhouette images extracted from Phylopic.org (License CC0 1.0 Universal Public Domain Dedication; credits: *P. vitulina*: Tracy Heath, 29 June 2013; *Z. californianus*: Margot Michaud, 4 April 2021; *U. maritimus*: Margot Michaud, 4 April 2021; *T. truncatus*: Steven Traver, 22 Feb 2012).

**Figure 2.**
Life expectancy and lifespan equality from 1 year of age by period for both sexes of zoo-held harbour seal (*Phoca vitulina*), California sea lion (*Zalophus californianus*), polar bear (*Ursus maritimus*) and common bottlenose dolphin (*Tursiops truncatus*). For comparison, sex-specific values from wild populations are plotted (note: credible intervals could not be calculated for wild populations): 1. Härkönen *et al*. [14], 2. Hastings *et al*. [18], 3. Hernández-Camacho *et al*. [17], 4. Delong *et al*. [19], 5. Lunn *et al*. [15], 6. Stolen & Barlow [16], 7. Mattson *et al*. [20]. See electronic supplementary material, table S1. Silhouette images extracted from Phylopic.org (License CC0 1.0 Universal Public Domain Dedication; credits: *P. vitulina*: Tracy Heath, 29 June 2013; *Z. californianus*: Margot Michaud, 4 April 2021; *U. maritimus*: Margot Michaud, 4 April 2021; *T. truncatus*: Steven Traver, 22 Feb 2012).

**Figure 3.**
Summary of long-term changes in female life expectancy and potential contributing factors for zoo-held harbour seal, California sea lion, polar bear and common bottlenose dolphin. Female life expectancy was derived from 1 year of age, and first-year mortality is shown in inset pie charts. See electronic supplementary material, table S6 for references and more details. AMMPA, Alliance Marine Mammal Parks and Aquariums; AZA, (American) Association of Zoos and Aquariums; CITES, Convention on International Trade in Endangered Species of Wild Fauna and Flora; EAAM, European Association for Aquatic Mammals; EAZA, European Association of Zoos and Aquaria; EEP, EAZA Ex-situ Programme; IAAAM, International Association for Aquatic Animal Medicine; IMATA, International Marine Animal Trainer's Association; SSP, Species Survival Plan; WAZA, World Association of Zoos and Aquariums; Z&A, zoos and aquariums. Silhouette images extracted from Phylopic.org (License CC0 1.0 Universal Public Domain Dedication; credits: *P. vitulina*: Tracy Heath, 29 June 2013; *Z. californianus*: Margot Michaud, 4 April 2021; *U. maritimus*: Margot Michaud, 4 April 2021; *T. truncatus*: Steven Traver, 22 Feb 2012).

See this image and copyright information in PMC

References

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Survival improvements of marine mammals in zoological institutions mirror historical advances in human longevity

Affiliations

Survival improvements of marine mammals in zoological institutions mirror historical advances in human longevity

Authors

Affiliations

Abstract

Conflict of interest statement

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References

Publication types

MeSH terms

Associated data

Grants and funding

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