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Palablu has been cooperating for quite a long time now with a group of researchers of the Institute for Marine Sciences of the National Research Committee in Ancona. Massimo Azzali, an engineer of the electronics department, is the person in charge and research coordinator. The research programme aims at studying the dolphins’ language by recording and analysing high frequency (> 20 kHz) and low frequency(< 20kHz) sounds. The Odontoceti produce a wide variety of sounds, starting from low frequencies, i.e. whistles, buzzes, yelps, clicks, etc, to ultrasounds which regulate their echolocation.
The echolocation is a sophisticated means of communication and self-communication only the cetaceans belonging to the suborder of the Odontoceti and a few more animals have, among them bats. By producing extremely high frequency sounds, called clicks, the Odontoceti can localize and identify an object in the water.
Thanks to this ability, dolphins can orientate themselves also in the most cloudy waters, distinguish objects having various shapes, consistencies and sizes without seeing them and find their preys. Inside the Palablu there is a room where the staff of researchers can acquire data and process them. The structure of Palablu is such that there are smaller pools adjacent to the main pool, where researchers can easily position their underwater equipment (cameras, hydrophones and sonar detectors), to record the impulses emitted by the dolphins and try to decipher them.
Researchers have started collecting data in 1997; they serve as basis for numerous works such as degree thesis for various Italian Universities (Milan, Palermo, Bologna, Turin, Padua), posters and scientific articles presented at various national and international congresses. Other degree thesis are currently under preparation.
Pregnancy lasts 12 months; during delivery the first part of the calf body to exit is the tail (breech delivery): in this way the blowhole, the slit located on the top of the dolphin’s head and through which cetaceans breath, is the last part of the body to touch the water and the calf, once being borne, is immediately in the right position to follow its mother to the surface and breath for the first time.
Usually labour lasts from 40 to 3 and a half hours.
Newborn dolphins are 90 cm long and their dorsal fin is slightly curved, with evident vertical bands on their mid sections (fetal bands): fins are still very soft and flexible to make birth easier and the bands are caused from being scrunched up in the mother’s placenta.
During the first months of life, the baby dolphin always swims next to its mother and is suckled every half hour. Nursing becomes increasingly less frequent and the baby dolphin starts eating fish when it is approximately 6 months old. Baby dolphins are definitively weaned when they are at least one and a half year old, and in any case before the next calf is born. During this phase, mother’s milk becomes a marginal part of the young dolphin’s diet.
Female dolphins reach their sexual maturity at 5-8 years, and their adult size at 7-8 years; male dolphins reach both adult size and sexual maturity at 8 years.
