Facts and fables about the animals at the Dolfinarium

The Dolfinarium has been around since 1965. In all those years a lot of knowledge has been built up about our own marine (mammals) animals and the marine (mammals) animals in nature. For example, by observing the daily behavior and health of the animals, or by conducting research.

There is a lot of talk about the animals in the Dolfinarium. That is why we want to distinguish facts from fables. Below we list the information about animal welfare, the living environment and origin of the animals in the Dolfinarium.

Animal welfare

Are the animals well off in the Dolfinarium and how can you determine the animal welfare level of the animals in the Dolfinarium?

When answering this question, it is important to look from the animal’s point of view. The ‘well-being’ of marine mammals is determined by, among other things:

the presence of sufficient food;
the absence of threats;
living in groups in which marine mammals are socially active, so also with each other.

All the above points apply in the Dolfinarium and we can therefore state that the animals in the Dolfinarium live in good conditions, with their well-being guaranteed.

We base this conclusion on the fact that we have specialized in caring for our marine mammals for over 50 years. Many behaviors that animals exhibit in nature (kind of own behavior), they also display with us. When the animals sometimes show deviant behavior, this is quickly noticed by our professional team of veterinarians and animal caretakers.

The Dolfinarium checks against animal welfare criteria from animal welfare studies* whether animals show any abnormal behavior (with regard to play, reproduction and enrichment). More information can be found at the link of Isabella Clegg’s well-being study. The animals are also continuously closely monitored by means of daily health checks. The animal caretakers recognize the behavior of the animals, which makes it possible to act preventively in the event of diseases.

The animal welfare level at the Dolfinarium is always valued at a high level by the government during inspections.

Why do you train the animals?

The marine (mammals) animals in the Dolfinarium are trained for four main reasons:

  1. Physical and mental stimulation (enrichment)
  2. Better care of the animals (medical training)
  3. Education to the visitors
  4. Research

In the Dolfinarium the animals do not have to hunt for their food. We therefore have to fill in the time they lose in nature in a different way. It is therefore necessary to challenge the animals physically and mentally.

Every day the animals are offered a very varied program, in which all kinds of different training courses are discussed:

  • Health training;
  • Educational presentations to the public;
  • Water training with the caretakers in the water;
  • Physical training such as natural jumps;
  • Training for research;
  • Enrichment or play sessions.

The zookeepers look at behaviors that the animals display in nature and try to teach the same behaviors to our animals. When teaching new behaviors, we work with a training method called ‘Positive reinforcement’. If the behavior is right, a positive stimulus is brought into their environment. This can be a primary reward, such as fish, or it can be a secondary reward such as attention from the caretakers in the form of caressing, clapping, cheering, or favorite toys for the animals, or giving ice cubes. This learned species-specific behavior is also shown during the various educational performances, so that visitors learn something about the species in the wild.

The animals are also given exercises, making it easier to care for them. This is called medical training or in English ‘Husbandry’. An example of medical training is, for example, the weighing position. The animals are taught to lie on a large scale. In addition, we can, for example, voluntarily take blood to see if they are healthy. The medical training is mainly intended to be able to monitor the health of the animals without having to catch the animals in a stressful way.

The carers have one main objective: no day should be the same. It is about a program that is as varied as possible for the animals.

Is the diet of the animals determined depending on their effort during the performance?

The animals are always fed. The diet of our animals therefore does not depend on their efforts during training sessions or presentations, but on a normal, healthy body weight (BMI). A large proportion of the animals are voluntarily weighed once a week, some animals are not weighed. A weekly optical condition check is done here, which looks at the appetite and behavior of the animal. These checks allow us to determine the diet of the various animals very accurately.

It may be that part of the daily diet is used to stimulate natural behaviour, for example by means of foraging enrichment. In that case, the situation in nature is imitated, so that the animal itself goes in search of food.

In addition, a reward does not only consist of food, but also of attention from the animal caretaker, contact with the caretaker and in the form of, for example, the animals’ favorite toys. The animals get those different kinds of rewards after they do something right. We only reinforce positive behavior during training, we try to convert incorrect behavior into something positive. If an animal does not want to participate in a training or performance, the animal will not be treated as incorrect. The caretaker will offer the attention and the fish diet in a different form. The animals are never punished under any circumstances. This type of training is also known as ‘Positive reinforcement’. That way we always manage to get the animals excited to work with us.

Is it true that captive dolphins live shorter lives?

Scientific studies show that dolphins age under human care than in nature. In the wild, dolphins live an average of 17 years. Factors such as overfishing, pollution of the sea, and noise pollution are the cause of the lower age of animals in nature. There are always exceptions: the oldest known living dolphin ever in the wild was 69 years old.

At 54 years old, dolphin Honey is the oldest dolphin in the Dolfinarium. Born in 1967, she is still fit and active, just like 47-year-old dolphin Prince.

The latest studies show that dolphins in the wild do not necessarily live longer than in captivity. The median age is often used in these types of comparisons. This means the age at which there are just as many animals that are older and younger. The data for the wild studies comes mainly from the so-called residence groups, including Sarasota Bay off the coast of America. The median age from 1 year for this group is 17.4 years. While the median age from 1 year for dolphins in zoos in America is 35 years.

How long do dolphin calves survive in the wild after birth?

One in two newborn dolphin calves in nature does not make it to the end of their first year of life. Many young wild dolphins die in the first two years of their lives, as do other young animals living in the wild. Young animals are very sensitive to diseases, natural enemies and natural disasters.

Studies of dead dolphins washed up in the Indian River in America show that 38% die before they reach the age of 2 and 64% die before they reach the age of 10 years. The last dolphin calf ‘James’ was born in the Dolfinarium in 2017.

Why don't the animals in the Dolfinarium get live fish?

It is not allowed by law to give the animals live prey. All the fish species we feed our animals are sustainably caught by an MSC certified company. Analyzes are taken of each batch of fish that show the moisture content and the calorific value. The polluting value is also determined. In this way we know exactly what our animals are ingesting. If both values ​​are not correct, the fish is not fed to the animals.

Living environment

What is the habitat of a dolphin?

Dolphins live in different habitats

  • On the coast in residence groups;
  • In migrating groups on the open sea.

Swimming in nature is mainly related to food search, socialization, flight from natural enemies or threats caused by humans. The habitat depends on:

  • Food availability
  • The absence of enemies
  • The presence of suitable reproductive candidates

If the above criteria are met, there is no reason for the group of dolphins to change their habitat and to travel greater distances in the sea to do so.

What about the dolphin habitats in the Dolfinarium?

In the Dolfinarium, dolphins live in two distinct and independent areas. The characteristics per area follow below.


  • A group of male bottlenose dolphins lives here;
  • The DolfijndoMijn contains about 3 million liters of artificial seawater;
  • Visitors have access to dolphin show and the dolphin panorama at the rear;
  • The area of ​​the performance, the back, and the part in between belong to the total habitat; The animals spend most of the day in the three basins, together in a social group.


Dolfijnendelta (Odiezee)

  • A mixed group of bottlenose dolphins lives here; mainly the young and older dolphins;
  • The OnderOdiezee contains about 13 million liters of semi-natural seawater;
  • Visitors have access everywhere and can admire the entire habitat.


Do the dolphins have enough space in the Dolfinarium?

The enclosed habitat of the dolphins in the Dolfinarium is no problem for dolphins as long as their health and safety is guaranteed. Although the Dolfinarium basin can never match its natural habitat, we also have many examples of bottlenose dolphins in the wild that do not swim long distances or have to dive deep to survive. We see this, for example, with resident or coastal dolphins. These groups of dolphins live in the shallow area off the coast, often with a maximum depth of 3 to 5 meters, and do not leave the area.

Swimming in nature is related to food search, socialization, flight from natural enemies or threats caused by humans. A convincing example of this is the presence of a large group of coastal dolphins in Sarasota Bay, which lives in a natural bay off the coast of Florida in America. The dolphins stay there in shallow water, and stay in that habitat because this bay is very rich in fish. This means they don’t have to swim miles to find their food. Other groups of coastal dolphins are found in Sado, Portugal and Moray Firth, Scotland.

The presence in a habitat is therefore mainly related to the availability of food and the absence of enemies or threats. Bottlenose dolphins are a very adaptable species that can easily adapt to its environment.

How can the dolphins in the Dolfinarium use their sonar?

Dolphins produce sound, called sonar, which they transmit forward. The echo that then bounces off the object in front of them, they capture using their lower jaw. They use their sonar for foraging for food, escaping natural enemies, navigating, staying with the group and communicating with each other.

Studies of sonar use in dolphins, both in the wild and in zoos, have shown that the animals can regulate the strength of their sonar and even turn it off and on. In 2017, the Boudewijn Seapark dolfinarium in Belgium participated in a scientific study by the University of Paris; they recorded the sonar* to learn more about the communication between our dolphins. This has shown that the dolphins do use their sonar, among other things for mutual communication.

* Lopez-Marulanda, J., Adam, O., Blanchard, T., Vallée, M., Cazau, D., Delfour, F. (2017). First results of an underwater 360° HD audio-video device for etho-acoustical studies on bottlenose dolphins (Tursiops truncatus)

Can the animals stand the sound and light effects that the Dolfinarium in DolfijnDomijn uses?

The Dolfinarium consciously deals with the sensitivity of dolphins to sound. We closely monitor the sound production in the basin for all sounds that penetrate under the water. This mainly applies to machines that have contact with the basins, such as pumps. Due to flexible placement on rubbers, noise pollution is prevented.

For sound produced in the air, above the water, there is a much smaller sensitivity in the animals. Most sound bounces off the surface of the water  back into the air (every diver or snorkeler can confirm that it is quiet under water).

The Dolfinarium has had sound investigations carried out by a company that specializes in acoustic investigations on marine animals. Dolphins perceive sound at different pitches than humans. The dolphins are not bothered by the performance sounds, such as the music from the performance. Humans can hear sound tones between the frequency range of 15 Hz to 20,000 Hz. This is different with dolphins. Dolphins’ hearing works especially well underwater. They produce high-frequency sounds for their sonar. Dolphins can therefore mainly hear sound tones between 75,000 Hz and 150,000 Hz, which are inaudible to humans. The hearing sensitivity of dolphins is thus far above the sound tones.

Origin of dolphins

Where do the animals in the Dolfinarium in Harderwijk come from?

The Dolfinarium last obtained animals from the wild in the 1980s. However, most of the animals were born in the Dolfinarium. In European animal parks, 70% of dolphins were born in a park. In the Dolfinarium, even 89% of the bottlenose dolphins were born in the Dolfinarium or in another animal park.

Wild dolphins have never been introduced into Europe from Japanese drives. The Dolfinarium strongly condemns these driven hunts and distances itself from them. That is why we actively participate in the international breeding program from the EEP (Endangered species Program).

Together with other parks we participate in the ‘breeding program’. In this way, together we have managed to stop taking animals from the wild for decades.

Did the Dolfinarium breed with dolphins?

The Dolfinarium has always had a successful breeding program. A birth creates new dynamics within an existing group of dolphins. The presence of young animals in a group of dolphins thus enhances and reinforces positive social behavior between all animals in the collection. It offers the females (the mothers, but also the aunts) the opportunity to experience very close social ties with the offspring.

Together with other animal parks, a so-called ‘breeding program’, or EEP, has been worked on since the start of the Dolfinarium. This is a reproductive program of the European zoo organization EAZA, in which the coordinator of this program is responsible for a healthy and genetically varied population within all European zoos. Such an EEP (European Endangered Species Program) program has also been set up for many other animal species within the collection of European zoos. In order to prevent wild capture and to keep populations of animals in zoos genetically healthy, animals are regularly exchanged between zoos.

Why did the Dolfinarium stop the breeding program?

However, part of a successful breeding program is also a stop when necessary, and the statement that it was decided earlier this year to stop the breeding program is incorrect. Since the takeover and change of management in 2015, the Dolfinarium no longer has an active breeding policy with dolphins. In 2017 it was decided to stop the reproduction of bottlenose dolphins at the Dolfinarium.

Reproduction policies for bottlenose dolphins in Europe have changed over the years, just as they regularly change for other zoo species. The current European bottlenose dolphin population today is sustainable for the future. The Dolfinarium has plenty of animals in the park. Through years of experience and success with bottlenose dolphins, the survival rate of the offspring is high and the genetic variation in European zoos is so good that further breeding is not necessary at this time. This is in line with the EEP (European Endangered Species Program) policy, which advises to temporarily stop reproduction in European zoos.

Will dolphins be bred again in the future?

The Dolfinarium does not intend to restart breeding with dolphins in the coming years.

A definitive breeding ban deprives these social animals of the opportunity to express essential and completely natural behavior patterns that enrich mother and calf. In addition, the presence of different ages is important for the entire social group. Other adult females can help raise the calves and young females are actively taught how to raise a calf. The presence of young animals, with a naturally playful mentality, challenging the older animals is a source of enrichment for all animals

A definitive breeding ban will negatively affect the welfare of the animals within the current collection in the dolfinarium in various ways.

A birth creates new dynamics within an existing group of dolphins. The presence of young animals in a group of dolphins thus enhances and reinforces positive social behavior between all animals in the collection. It offers the females (the mothers, but also the aunts) the opportunity to experience very close social ties with the offspring. This also reduces the compulsive behavior of the males towards the females, when they can reproduce naturally.

In addition, long-term use of contraception can cause veterinary problems in the female animals, which also negatively affect the well-being.

However, a definitive breeding ban is more likely to negatively affect the well-being of the current population of bottlenose dolphins. The European zoo organization EAZA is also against a permanent breeding stop for bottlenose dolphins. As for other animal species that live in a social group, the birth of offspring for a group of bottlenose dolphins is essential for expressing completely natural behaviors. Birth creates a new dynamic within an existing group of dolphins. We believe in controlled and coordinated reproductive programs in zoos. Directed by the European zoo organization EAZA.

In the wild, dolphins live in complex family bonds. What about in the Dolfinarium?

Dolphins (in nature) live in so-called ‘fission-fusion’ relationships. This means that group compositions are constantly changing in composition and size. Bottlenose dolphins are social, very adaptable and have excellent adaptability.

Entire families also live in the Dolfinarium. However, dolphins sometimes move to other parks. However, this is done in a very careful manner. It is important to know that moving an animal is not negative for an animal. It is often also a challenge for the newcomer and the group in which he or she ends up. Their trusted caretakers prepare the animals for transport. In fact, during and after arrival, these caretakers guide the animals in exploring and discovering their new habitat and congeners.

* Venn-Watson, S.K., Jensen, E.D., & Ridgway, S.H. (2011). Evaluation of population health among bottlenose dolphins (Tursiops truncatus) at the United States Navy Marine Mammal Program. Journal of the American Veterinary Medical Association, 238(3), 356-360.


Does the Dolfinarium comply with all standards and legislation?

Dolfinarium has a zoo permit from the Dutch government. The Netherlands Enterprise Agency publishes on its page which zoos in the Netherlands have a permit. See https://www.rvo.nl/onderwerpen/agrarisch-ondernemen/dieren/dierenwelzijn/zoo. A zoo is licensed if: According to the Animal Keepers Decree, a zoo is a “permanent establishment where live wild animals are kept for display to the public for at least 7 days a year, with the exception of circuses and pet shops.” You need a permit to operate a zoo. A zoo retains its license through: periodic inspection and compliance with the license of the NVWA.

Following the last visitation at the end of 2019, the Dolfinarium recently made agreements with the Ministry of Agriculture, Nature and Food Quality. To the satisfaction of the Minister, it has been agreed that the Dolfinarium will commit itself in the coming years to:

  • A more natural dolphin enclosure in ‘DolfijnDomijn’ and larger enclosures for the other animal species. After the approval of the ministry, the plan is to implement this in the coming years;
  • The continuation of a new educational route since 2020.

This has given all animal shows an educational character, with the dolphin show Oceanica as the largest educational example. In addition, the animals only display natural behavior and only unnatural behavior if this supports the educational message to the visitor.

Finally, it is important to indicate that the animal welfare level at the Dolfinarium is always valued at a high level by the government during inspections.

The Dolfinarium also complies with all European requirements described in EU Directive 1999/22/EC on ‘the keeping of wild animals in zoo’. The Dolfinarium is a member of the EAAM (European Association for Aquatic Mammals; www.eaam.org). This is an organization that shares knowledge among dolfinariums, trainers, veterinarians, researchers and students. The EAAM imposes very strict guidelines on its members for keeping marine mammals. Members must comply with these rules and are regularly monitored. The EAAM is the only European organization that represents the interests of marine mammals. The Dolfinarium was inspected in 2017 and was then accredited in accordance with all EAAM guidelines.

What does the Dolfinarium do with regard to education?

The Dolfinarium aims to introduce its visitors to special marine mammals and the dangers of plastic soup in the sea. By bringing visitors face to face with our animals during eight educational performances and the inwater program, we hope that people will become directly involved with our animals. They learn a lot about marine mammals and the way of life of their congeners in the wild. In addition, they are informed about the problem of plastic soup for the animals in the sea. In this way, we hope that our visitors will play an active role in preserving the various species in nature after their visit to the Dolfinarium.

There are also two educational areas in the park, which provide information about the biology and ecology of the various marine mammal species in the wild. During our educational programs for schools, students receive a lot of information about the species and their habitat in nature from our professional team of caretakers.

Does the Dolfinarium participate in scientific research?

Yes, the Dolfinarium regularly participates in national and international research projects. For example, we have participated in studies such as:

  • Growth curve check using drones Porpoises
  • Blood test Porpoises
  • Blood Test Walrus
  • Animal Welfare Research Dolphins
  • Cortisol Research Dolphins
  • Arctic Marine Litter Project, Wageningen University
  • Research sharks
How does the Dolfinarium contribute to nature conservation?

The Dolfinarium contributes to the conservation of the species in the wild in various ways:

  1. Visitor education; visitors point out the fragility of nature and what active role they themselves can play in protecting the species in the wild;
  2. Research; increasing knowledge about the species, so that we can protect them more effectively in nature;
  3. Collaboration with EAAM; conservation project to protect monk seal in Mediterranean sea.
  4. Collaboration with knowledge partners Plastic Soup Foundation and financial support of the Arctic Marine Litter Project for the purpose of informing visitors about the dangers of plastic soup in general, as well as for the animals in the Arctic.

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