Pinnipeds in Captivity

Seals and sea lions are common and widespread within the animal display industry. Many zoos, aquaria, and marine parks exhibit seals and sea lions, often presenting public seal shows; these exhibits and shows are among the most popular zoo attractions. Reasons for holding marine mammals in captivity include display in zoos and aquaria, scientific research purposes, military work, swim-with-cetaceans programs, and rehabilitation to care for stranded individuals. While there exists less controversy over holding seals in captivity than cetaceans, standards for care and quality and size of exhibit space vary as do the welfare of individuals in these facilities.

History of pinnipeds in captivity

Polar bears (Ursus maritimus) and various pinnipeds were probably the first marine mammals to be held in captivity (Perrin et al. 2002). Walruses (Odobenus rosmarus) were held in captivity as early as 1608, while polar bears were in captivity in 1060. One of the first records of pinnipeds in captivity is a Mediterranean monk seal (Monachus monachus) brought into captivity in 1760 (Maxwell 1963).

Most pinnipeds and some sirenians began to appear in exhibits in the late 1800s and early 1900s (Perrin et al. 2002). Thirty-three species of pinnipeds have been held in captivity and 22 species have reproduced successfully in captivity. The California sea lion (Zalophus californianus) is now the most common pinniped in captivity, due to its ability to breed readily in captivity, a receptivity to training and performing, a hardy constitution, and accessibility in the wild (Reeves & Mead 1999). Harbour seals (Phoca vitulina) are also common in zoos and aquaria in north America and Europe and have successfully reproduced. In recent years, most pinnipeds in captivity are not captured from the wild but come from captive breeding programs or from stranding networks and rehabilitation centers (Wilkinson & Worthy 1999).

Differences in captive environments

In zoos and aquaria, seals are either kept alone or in groups, while sea lions are most often housed in groups, reflecting their very obvious gregariousness in the wild. However, the size of pool and resting areas on land vary dramatically in different facilities. Pools vary from small (2 meters by 3 meters) to large (50 meters in length). Larger pools and haul-out areas may alleviate some of the stereotypic or patterned swimming that can be common in captive marine mammals (R. Schusterman, pers. com.).

Seals and sea lions in various captive facilities have access to differing amounts of enrichment, training, and some perform for public shows. They are intelligent, have strong sensory capacities and tend to be highly trainable[1]. Training is common in many species in zoos and aquaria, in part to create a routine of human contact that facilitates medical examinations and treatments when those are necessary¹.

Issues of welfare and well-being in Captivity

Individuals in captivity cannot express their natural behavioral repertoire. They cannot engage with their environment or express their preferences. They cannot forage for food, may not be able to create social bonds of their choosing and ultimately cannot control their environment, which is considered to be a factor in the welfare of animals (Wiepkema 1985). Stereotypic behaviors, which are generally behaviors that are repeated over and over, are common in animals living in zoos. Pacing in terrestrial mammals, patterned swimming in circles in marine mammals, or head bobbing in and out of the water are all examples of stereotypies.

The concept of boredom in non-human mammals in captivity is very relevant to understanding the welfare needs of pinnipeds in captivity. Boredom has been defined as impaired ability to actively focus attention upon, and interact with, the environment (F. Wemelsfelder[2]). If we understand that the organisation of a seal’s behavior in the wild is primarily regulated by external stimuli (such as the seal’s haul-out site, the dynamic marine environment, location and movement of prey species, navigation cues, social companions, tides, weather and sea condtions, etc), we begin to understand how impoverished that animal’s life in an aquarium will be with most or all of these all of these stimuli being absent from the captive environment. It is also understood that intelligent mammals such as pinnipeds also seek novel and varying stimuli through exploration and play. Here, again the scope for investigating novel stimuli is limited or non-existent in most captive pinniped facilities. Wemelsfelder proposes that in long-term captivity animal behavior gradually loses its active and flexible character. Animals that have developed stereotyped behavior may persist in such stereotypies even when transferred to a more enriched environment or exposed to novel objects.

Enrichments have been introduced to many facilities to improve ‘well-being’ by alleviating boredom and stereotypic behaviors. These might include balls or toys in the pools, devices similar to dog toys that release food as they are moved around, and large ice cubes that contain fish pieces inside. One study of a group of seals at Baltimore Aquarium demonstrated that the introduction of various objects stimulated exploration and random swimming and reduced patterned (stereotypic) swimming (Hunter et al. 2002). A study is currently underway in aquaria in the UK to study the effects of introducing a ‘fish ball’ to captive seals (C. Stainfield, pers. com.). Machines that create wave patterns, as the National Zoo in Washington DC, USA plans to add to their new sea lion exhibit[3] may add enrichment. Both seals and sea lions can respond well to human interaction and zoos and aquaria could incorporate more human/ seal contacts as another enrichment. Lastly, there is no doubt that different kinds of pinnipeds appear to thrive in the artificially stimulating environment provided by top laboratories conducting research into cognition and sensory systems¹.

However, most captive environment enrichment efforts seem to be ad hoc, with no overall guiding principles. Wemelsfelder emphasized the need for a combination of measures to provide meaningful enrichment for the animals. Social animals, such as most pinniped species, require companions in captivity, and should not be kept solitarily. Companions can provide an endless variety of meaningful stimulation, but this may only occur to the animals’ benefit if other aspects of the environment, such as physical attributes of the pool and feeding schedule, are also appropriately designed to recognize the interdependence of enrichment measures. One interesting study of a captive group of harbor seals demonstrated the way in which a complex method of ‘earning’ fish by the seals became integrated with social relationships and cooperation amongst the group (Markowitz, 1978). The development of a set of guiding principles for maintaining pinnipeds in zoos and aquaria, will be one aim of a study currently being started under the auspices of the Seal Conservation Society (see Projects section). These principles must take into consideration the wide range of interspecific differences in types of sociality and physical environment of pinniped species.

Is captivity suitable for marine mammals?

The Seal Conservation Society study to develop guiding principles for pinnpeds in captivity does not imply that the Society necessarily condnes the keeping of pinnipeds in captivity. Here we consider some more fundamental questions concerning the keeping of pinnipeds in captivity.

Do the benefits to humans from the animal display industry justify the animals’ confinement and stress associated with the unnatural environment? Although captive harbour seals and California sea lions may live longer than individuals in the wild and can breed (unlike dolphins and whales that often die prematurely in captivity and do not breed easily), the question remains for all marine mammals whether captivity is justified for entertainment, educational or conservation purposes.

A study by the American Zoo and Aquarium Association (AZA)(Falk et al. 2007) found that zoos and aquariums have a long-term positive impact on visitors’ attitudes towards animals. But subsequent to that study, Marino et al. (2010) examined the methods used in the AZA study and found significant methodological issues that nullify the claims of that first study. The justification for captivity for entertainment or educational purposes becomes more questionable as animal welfare concerns grow and human understanding of animal intelligence and capacities broadens.

A further justification for captive pinnipeds to be considered is the research value of captive studies, such as are carried out by institutions such as the University of Rostock in Germany, the Long Marine Lab at the University of California, Santa Cruz, and the Sea Mammal Research Unit at the University of St Andrews in Scotland, UK. Where the research clearly increases our understanding and appreciation of pinniped species, this benefit must be considered in the context of the welfare and well-being of the animals involved. Our society would tend to support those facilities where the animals’ long-term well-being and welfare is evident and is a priority of the institution.

Sources

Falk, J. H., E. M. Reinhard, C. L. Vernon, K. Bronnenkant, N. L. Deans, J. E. Heimlich. 2007. Why zoos and aquariums matter: Assessing the impact of a visit to a zoo or aquarium. Silver Spring, MD: Association of Zoos & Aquariums.

Hunter S.A., Bay M.S., Martin M.L. and Hatfield J.S. 2002. Behavioral effects of environmental enrichment on harbor seals (Phoca vitulina concolor) and gray seals (Halichoerus grypus). Zoo Biol 21:375–387.

Marino, L. S. O. Lilienfeld, R. Malamud, N. Nobis, and R. Broglio. 2010. Do zoos and aquariums promote attitude change in visitors? A critical evaluation of the American Zoo and Aquarium study. Society and Animals 18: 126-138.

Markowitz, H. 1978. Engineering environments for behavioral opportunities in the zoo. Behavior Analyst 1: 34-47.

Maxwell, G. 1967. Seals of the world. Houghton Mifflin: Boston, MA.

Perrin, W. F., B. G. Wursig, and J. G. M. Thewissen. 2002. The Encyclopedia of Marine Mammals. Academic Press: San Diego, CA.

Reeves, R. R. and J. G. Mead. 1999. Marine mammals in captivity. Pages 412-436, In J. R. Twiss and R. R. Reeves (eds.), Conservation and management of marine mammals. Smithsonian Institution Press, Washington D.C.

Wiepkema, P. R. 1985. Abnormal behaviors in farm animals: ethological implications. Netherlands Journal of Zoology 35: 279-299.

Wilkinson and Worthy. 1999. Marine mammal stranding networks. Pages 396-411. In J. R. Twiss and R. R. Reeves (eds.), Conservation and management of marine mammals. Smithsonian Institution Press, Washington D.C.