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The ability to reason about
objects that have disappeared from view, which is known
as object permanence, has been studied in many terrestrial
animals, but DRC is the first to explore this with
marine mammals.
In this study, we taught our dolphins
a game in which we hid an object in one of three buckets,
and then asked them to find it. ("Where is it?")
The question was whether they would track the object,
and then keep in mind where the object was located. They
did. However, we also discovered some tasks they couldn’t
do – such as when we placed the object in a bucket,
and then moved the bucket. It's not certain why that
task was difficult. One possibility is that they might
lack an understanding of moving containers (which don't
exist in their natural environment). Another is that,
due to echolocation, they don't need the ability to mentally
track an object that disappears from view. Further research
can help us figure out this puzzle.
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Which
bucket contains the hidden object?
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Tanner
investigates the scientific journal Animal
Cognition, where DRC
published our findings
about what dolphins understand about hidden objects.
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FETAL ECHOCARDIOCRAPHIC EVALUATION
OF THE BOTTLENOSE DOLPHIN: |
During
human pregnancies, a variety of clinical tests and procedures
are conducted to provide information about the developing
baby. One such procedure, fetal echocardiography, uses
sound waves (ultrasound) to study the structure and function
of a baby’s heart
before birth. DRC regularly uses ultrasound as a helpful
diagnostic tool to monitor our dolphins’ health in
other areas. Could fetal echocardiography be adapted to
pregnant dolphins and their calves? Dr. Mark Sklansky,
the Director of the Fetal Cardiology Program at the Children’s
Hospital in Los Angeles, came to DRC to investigate.
Working with several members
of DRC staff and our veterinarian, Dr. Sklansky was able
to apply his techniques to evaluate the cardiovascular
health of four calves prior to birth. Combined with similar
work at other facilities, he has concluded that fetal
echocardiography can safely and effectively evaluate
a calf’s heart. This has the potential to
be a valuable clinical tool for monitoring our dolphins’ pregnancies.
In addition, further research may help to increase the
overall understanding of calf cardiovascular development
and the specialized adaptations of marine mammals. |
Dr. Sklansky uses ultrasound to look within a pregnant
dolphin,
to study the calf’s heart.
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NUMBERS
CONCEPTS: |
The ability to understand number
and counting is often thought to be specific to humans.
Over the last few decades, studies have shown that terrestrial
mammals and birds can understand various numerical concepts,
and that in primates at least, these numerical concepts
can be very advanced.
There are at least four types of skills that underlie
basic human competence with number and math.
- Recognizing numerosities – distinguishing, for
example that “threeness” is different from “twoness”;
i.e., knowing that a set of 3 objects is distinct
from a set of 2 objects.
2 rocks in one hand, 4 in the other
- Understanding relative numerosity – realizing
that numbers form an ordered series,
incorporating the relationships of more and less;
i.e., 1 is less than 2, 2 is less than 3, and so
forth
Quantities can be arranged in an order, from less
to more.
- Mapping numerosities to symbols – learning for example that “1” goes with “oneness”, “2” goes with “twoness”.
-
Manipulating
numerals – e.g.
addition and subtraction.
Symbols can be manipulated, just like the objects
themselves.
Do dolphins have the
capacity for these kinds of skills? If so, what
are their competencies in relation to the rest
of the animal kingdom and to human child development?
DRC’s Research Department, led
by Dr. Kelly Jaakkola, is addressing these questions.
In our “Less” project,
we researched the ability of dolphins to understand
the first two concepts -- numerosity and relative
numerosity. Two of our dolphins, Talon and Rainbow,
participated in this study. We began by showing
each dolphin two boards with different numbers
of dots on them: 2 and 6, for example. First, we
asked them to always pick the board with 2 dots
on it, no matter where the dots were on the board
or what size they were. Learning this task meant
that Talon and Rainbow understood that 2 is different than
6, which is the concept of numerosity. The next
step was to test with other number pairs that were
new to the dolphins, and always ask Talon and Rainbow
to choose the board that had the fewest dots on
it. The ability to pick out the smaller number
without being trained on that specific number pair
meant that they understood the concept of “less”(i.e.
relative numerosity).
Talon choosing the board with “less” dots.
Rainbow studies the
Journal of Comparative Psychology,
where the “Less” study
was published.
Read about the study in
the American Psychology Association's Monitor on Psychology
(Vol.
36, No. 8) Click
here.
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CALF
SOCIAL DEVELOPMENT: |
Mother-calf social interactions
are very difficult to observe in the wild, so valuable
information can be learned from every calf born at DRC.
The social development of each calf is monitored closely
to determine how much time the calf spends with his or
her mother, how much time is spent with other lagoon-mates,
and how much time is spent alone.
Changes in independence are tracked over time so that
eventually, different mother-calf pairs can be compared.
Particularly interesting will be comparisons involving
the same mother with successive calves so that we may see
if birth order has an effect on parenting style. In addition,
we will be able to assess whether previous experience as
a babysitter, or alloparent in scientific terms,
can be used as a predictor of good maternal care when the
alloparent becomes a parent.
Tursi and Gypsi
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MONITORING
HEALTH AND WELL-BEING:
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Staff at DRC collect data under
a variety of circumstances to monitor the general health
and well being of our family of dolphins and sea lions.
For example, if a dolphin moves into a new lagoon, we want
to ensure that (s)he is comfortable in that new environment
and social grouping. If a dolphin is feeling a little under
the weather, we may monitor their respiration rate.
Information like this can help us to make decisions to
promote the health and happiness of the dolphins and sea
lions that call DRC home.
To ensure observer’s reliability
in dolphin identification, Emily Guarino, Admin. Director of
Research, applies harmless zinc oxide to Tanner’s
dorsal fin.
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DOLPHIN
TRACKING IN A HURRICANE EVENT:
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Located on Grassy Key, Florida,
DRC faces the possibility of hurricanes striking the area
each year. Depending on the severity of a storm, some dolphins
may feel more secure seeking shelter in deeper water away
from shore. Once the storm has passed, it is critical that
we are able to quickly find any dolphins that do not return
on their own, as animals that live in human care lack the
necessary skills to survive in the wild.
Over the years, DRC staff has
worked on several different approaches to assist in recovery.
Every dolphin at DRC has been trained to respond to a
recall device (a "pinger").
This behavior is practiced and reinforced regularly. In
order for this to be effective, however, the dolphin must
be within a 1-2 mile range of the recall device. To place
human rescuers within this range, DRC has sought to mark
the members of its colony in a readily recognizable way.
It is believed that if a dolphin were lost, (s)he would
seek out humans for assistance, increasing the likelihood
of the public spotting the dolphin. Once the sighting was
reported, DRC staff would be able to use the recall device
in that area.
We have developed bands that
are custom fit to each dolphin’s
peduncle (the portion of the tail just before the flukes).
Made of a durable, but pliant material, the bands are brightly
colored so that when a banded dolphin is spotted, (s)he will
be immediately identifiable as a dolphin that belongs at
DRC.
Since dolphins in the
wild don’t accessorize,
these dolphins are
identifiable as residents of
DRC.
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BIOLOCOMOTION
(TAIL-WALKING):
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| Dolphin Research Center is participating
in a study by Prof. John Bush and Dr. Matthew Hancock of
the Massachusetts Institute of Technology, and Prof. Frank
Fish of West Chester University. These scientists are looking
at the ability of dolphins (and some fish) to walk on their
tails with the bulk of their body above the water. This ability
is referred to as tail-walking, and is a common trained behavior
for the dolphins at DRC.
Rainbow demonstrates his powerful tail-walk.
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MARINE
MAMMAL STRANDINGS:
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For many
years, DRC was a member of the Southeast
Stranding Network. The DRC Marine Mammal Rescue
Team played an important role in strandings and rehabilitation
efforts. Unfortunately, the causes of strandings are
often unknown. Illness is one possibility. For the safety
and well being of the dolphins that live at our facility,
DRC prudently pulled back from on-site assistance. While
we continue to provide a great deal of resources, support,
and knowledge to other teams assisting in dolphin and whale
strandings, we must safeguard our own pod.
DRC plays a major role in manatee
rescue in the Florida Keys. To learn more about DRC’s
Manatee Rescue Team and how you can help click
here.
Our involvement with strandings contributed a great deal
of information to the scientific community. Marine mammal
strandings provide invaluable opportunities to study species
which may otherwise provide only fleeting glimpses at sea.
As a member of the Southeast Stranding Network, the DRC Marine
Mammal Rescue Team not only provided medical attention for
living stranded animals, but collected massive amounts of
data.
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SIGNATURE
WHISTLES:
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Each dolphin is believed to have a unique, stereotypic
whistle called a "signature whistle". The individual
whistle is developed during the first few months of life,
and it has been observed that dolphins may imitate the
signature whistle of a close companion. Because each dolphin
produces a distinctive whistle, it may be possible for
a dolphin to identify other individuals by their signature
whistles. These whistles are thought to maintain contact
between animals that are out of sight of each other.
Drs. Peter Tyack and Amy Samuels, along with Rebecca
Thomas and Stephanie Watwood, all from Woods Hole Oceanographic
Institution, investigated signature whistles and other
vocalizations of our dolphins. They installed an array
of hydrophones and an overhead video camera in our lagoons.
With a special computer, underwater sounds were triangulated
to pinpoint which individual was making a particular sound.
Behavioral observations of the dolphins provided social
context for these whistles in the unique natural environment
at DRC. |
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METACOGNITION
IN DOLPHINS:
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A fundamental
characteristic of higher levels of consciousness is the
awareness of one's own thoughts and feelings. Do dolphins
have this kind of awareness? This was the question addressed
in a study by Jonathan Schull of Haverford College and
David Smith of the New School for Social Research.
In the experiment, the dolphin, Natua, heard either a
variable low tone or a high tone, and learned to press
corresponding paddles. Natua had no difficulty with most
of the trials. But on some trials, the variable tone would
approach the pitch of the high tone, which made it difficult
to determine if it was to be considered high or low. These
crucial trials were too difficult for the dolphin to be
sure of success. On these trials, the dolphin could make
a special response to ask for an easier trial, but it would
only make sense to do that if he knew that
he didn’t know the
answer.
Schull and Smith pointed out that by "bailing out" of
these most difficult trials, Natua demonstrated that he
was aware of his own doubts, and that he could think about
his own thinking. This ability is known as metacognition.
The data produced was comparable to that collected for
humans and rhesus monkeys.
Natua, who participated in this study.
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IMMUNOLOGY:
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When we're
not feeling well, a doctor may take a blood sample to try
to determine why. Dolphins are no different. Veterinarians
can tell a great deal about the health of a dolphin by
analyzing a blood sample. However, the information known
about dolphin blood samples is less detailed than what
we know about human blood. DRC worked
with Dr. Jeffery Stott, an immunologist from the University
of California at Davis, in order to learn more about dolphin
immunology blood profiles. Whereas veterinarians can typically
detect an active infection in a dolphin by counting the
number and type of white blood cells present in a blood
sample, Dr. Stott is creating a complete immunological
profile that includes the analysis of each subtype of white
blood cell as well as how well those cells are functioning.
Dr. Stott is collecting blood samples from dolphins that
live in a variety of environments: DRC's natural seawater
lagoons, aquariums, and the free-ranging dolphins of Sarasota,
FL. By collecting blood from dolphins that live in each
of these environments, he will be able to develop a very
detailed profile of what is normal in each circumstance. |
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PREDICTABILITY
OF DOLPHIN BEHAVIOR
DURING STRUCTURED SWIMS:
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DRC has
always believed strongly that programs that allow guests
to enter the water to swim
with dolphins should be specifically directed by experienced
trainers. We structure our programs accordingly. This belief
was verified by an independent study published in 1995,
which concluded that programs like ours do not pose any
significant risks to dolphin or human participants.
A guest enjoys a kiss – one of the specific behaviors
in our structured swim.
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LEARNING
WITH DOLPHINS VS. LEARNING WITHOUT DOLPHINS:
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Would the
presence of dolphins act as reinforcement to help increase
learning for children with mental disabilities? Dr. David
Nathanson came to DRC to investigate. Six children were
taught new vocabulary words through interaction with dolphins.
Results indicated the children learned two to ten times
faster and with greater retention when working with the
dolphins. Benefits included increased evidence of the efficacy
of using non-human species to increase attention, elicit
speech, and increase memory for people with disabilities.
One question remained: was it the dolphins’ presence
that made the difference, or simply being in-water?
To find out, he then compared the effectiveness of in-water
work without dolphins to in-water work with dolphins on
the learning improvement of children with mental disabilities.
Sessions without the dolphins were conducted out of sight
of the dolphins at a nearby beach, and the reinforcement
for a correct response was the child's favorite water toy.
Significant improvements in responses occurred when interaction
with dolphins was used as reinforcement, compared to responses
made when reinforcement was a favorite toy. Water work
with dolphins evoked both a greater number and higher level
of responses. |
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DOLPHIN
DETECTION OF OIL FILM:
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The objective
of this study was to determine if bottlenose dolphins could
detect an oil slick on the surface of the water. In the
initial experiment, the dolphins viewed a transparent cylinder
and learned to press a paddle when they detected something
in the cylinder besides water. It was demonstrated that
dolphins could discriminate between oil and the uncontaminated
surface of the water.
This project also showed that dolphins would avoid an
oil slick, as they would hesitate to swim beneath one when
detected. Their few contacts with the oil (either accidental
or as part of an investigative process) resulted in an
overt startle response, which set a pattern for subsequent
avoidance.
Overall, the dolphins avoided oil both during the day
and at night, although the response broke down when the
threshold of their ability to detect the oil was reached.
Visual cues were instrumental in the dolphins' detection
of the oil, and tactile sense played the most important
role in their response to the oil. Memory of its location
influenced their behavior, even after the oil was removed. |
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DNA
PATERNITY TESTING:
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Rainbow and Pax, shown by DNA tests to
be father and son.
DRC has a
long history of successful dolphin births. Since we have
always structured our dolphin living arrangements based on
personalities and what we know of natural dolphin society,
there often has been more than one mature male present when
a female conceives. Prior to new developments in paternity
testing, we had no reliable method of identifying a calf's
father.
DNA Fingerprinting
In the 1980s, DRC began a genetic study to develop a method
to determine paternity in conjunction with Dr. Debbie Duffield
at Portland State University. Dr. Duffield extracted chromosomes
from blood samples taken from our dolphin colony and compared
them to determine paternity. By the early 1990s the technology
available to Dr. Duffield had improved considerably thanks
to advances in human paternity testing. The improved technique,
called DNA fingerprinting, produced results much faster than
the older chromosome analysis. Dr. Duffield first tested
dolphins whose paternity had been formerly determined with
chromosome analysis. The results were identical, proving
that the new technique was valid for dolphins. Thanks also
to DRC’s careful record keeping, Dr. Duffield was able
to further demonstrate the accuracy of DNA Fingerprinting
with newer calves because she knew exactly which male dolphins
were candidates for father of a particular calf. As a result
of this testing, DRC knows the fathers of the dolphin calves
born at DRC.
DNA Microsatellite
As technology advanced, Dr. Duffield improved the methodology to conduct dolphin
paternity tests. The newest technique, using microsatellites or specific pieces
of DNA, is a great improvement over DNA fingerprinting for analyzing the genetics
of wild populations. With DNA fingerprinting, Dr. Duffield had to test every
possible father along with the calf and its mother at the same time, very inconvenient
when numerous males are candidates for the father in a wild population. Results
could not be compared between tests, so with each new calf, all of the fathers
had to be tested again.
Microsatellites, on the other hand, are easily extracted from a dolphin blood
sample for analysis. Once analyzed, the specific pattern for each dolphin can
be documented for future comparison.
To test the microsatellite technique, Dr. Duffield ran samples from Rainbow,
Sandy, Tursi, and Pax. Because DRC knew that only Rainbow or Sandy spent time
with Tursi, Dr. Duffield was able to show that the new technique accurately
predicted Rainbow as Pax’s father. Dr. Duffield is now using this technique
with the wild dolphin population under study in Sarasota, FL.
DNA tests can help DRC quickly and accurately determine the paternity of our
calves in the future. This knowledge of the family history of our calves is
critical to future planning for our breeding colony.
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