Zoology is the branch of biology that studies the animals. This discipline researches all aspects of these living beings, such as their biology, physiology, morphology, behaviour, distribution and ecology of each species. In order to develop this activity, the zoologist analyses and manipulates the specimens, which requires creating animal collections and preserving them in the best possible conditions. This is the reason why zoological collections are decisively important for the development of Zoology. Each group or structures of animals form a collection depending on its composition, texture and nature, which requires specific conditions for its preservation. Some of them are dried preserved inside established ranges of temperature and humidity, meanwhile other specimens need to be kept inside specific preserving liquids, resins, freeze-dried, deep-frozen, etc. Over time, zoological collections have increased considerably and nowadays they can be found at the best universities, museums and research centres from all over the world.

History of the vertebrates zoological collection

Most of the taxidermied animal collections belonging to the Universitat de València used to be at the Natural History Cabinet, where La Nau is placed, in Valencia. The specimens were displayed from the second half of the 18th century in a series of glass cabinets glass cabinets in the upper floor of the historical building, home to the founded University at the end of the 15th century. In May 1932, a fired devastated the whole south wing of the building and it affected mainly the collection room of the Cabinet, which resulted in the lost of most specimens of the collections. According to sources of that time, during the fire a voluntary group of students was rapidly created. They were present at the moment of the fire and, obviously, along with firemen and local authorities retired many specimens of the collection before they were reached by the flames. These specimens were placed temporarily on the close Patriarca Church, until they were again relocated to the new facilities of the Universitat. Since then, the collection has grown thanks to several donations of institutions and private citizens, and also by the compilation and preparation of samples carried out by the university staff. Nowadays, it counts on almost a thousand specimens of different vertebrates’ groups.

Taxidermy

Taxidermy, from the Greek word “taxisa” (repair or arrangement) and “dermis” (skin), it is defined as the art of stuffing animals in order to preserve them with the appearance of living animals and to facilitate its exhibition, study and preservation. Basically, it consists on the removal of the skin, its tanning, treatment and disposition on a mould that imitates the natural form of the specimen. This technique was greatly accepted from the end of the 18th century until the beginning of the 20th, since it allowed the preservation of part of the zoological material to its scientific study. Besides, it also facilitated to the contemporary society the possibility of contemplating exotic animals difficult to be observed out of their natural habitats. At that time, along with engravings and illustrations, it was the only way to get a sense of these animals. For that reason, most of the musems and institutions’ collections preserve a lot of specimens preserved by taxidermy, although nowadays this form of preservation is in disuse. Currently, the skins are preserved without aggressive treatments, on dry and without moulds, under strictly controlled temperature and humidity conditions.

Mammals: Generalities

Mammals are a taxonomic group of the vertebrates. Its origin dates back to 200 million years and they emerged from certain reptiles currently extinct. Primitive mammals species were small in size and nocturnal. They cohabitated along with the dinosaurs, which were dominant back then. After the extinction of the dinosaurs, the mammals experienced the awakening that lead them to the dominant position from the Cenozoic era until our days. In the evolution of the mammals can be observed a clear tendency on the activity increase, the improvement of animal locomotion and the progress obtaining and processing food. Current mammals are divided into three groups, depending fundamentally on the way in which their offspring develop. Monotremes, born from eggs; Marsupials, which complete most of the embryonic development out of the uterus, in a structure denominated pouch; and Placentalia, the majority nowadays, in which the development of the embryo takes place completely inside of the uterus and it is fed by a temporary organ, the placenta.

Lion Skeletons: South American sea lion

These two skeletons represent vertebrates belonging to the group of mammals. During the evolution of this group it can be observed a tendency to the simplification of the skeleton regarding the line of reptiles from which they come from. The ribs are reduced to the thoracic region, along with the appearance of the lower spine and the backbone, and also a parasagittal disposition of the limbs, which allow them to bend the body in the sagittal plane increasing the size of the stride, favouring a major efficiency in locomotion. The skeleton simplification it is also observed in the cranium with the lost or reduction of cranial bones, modifications on the mandibular articulation and a dental specialization. In particular, these skeletons belong to an African lion (Panthera leo) and a South American sea lion (Otaria flavescens). Both species are carnivorous. The first one feeds from prey (fundamentally other mammals). It stalks and catches them with its claws. The second one is a predator of fishes and molluscan cephalopods. The developed dentition is very similar in the two species, due to the analogue carnivorous diet they consume.

Generalities and cetaceans' creniums

Cetaceans are a group of mammals with complete adaptation to water life, completely independent from the terrestrial environment. Their forelegs have turned into flippers and their hind legs have disappeared. Their whole body has acquired an hydrodinamic form. Mollecular studies prove that nowadays the closest terrestrial relatives to the cetaceans are the hippopotamus. There are currently 89 species, mostly divided into two groups. The first one belongs to the Odontoceti - also toothed whales, characterized for having teeth and a diet based on fishes and cephalopods, mainly. Dolphins, long-finned pilot whales, orcas, mereswines, narwhals, white whales, sperm whales and whale calves belong to this group. The second group gathers the Baleen whales or whalebone whales, without dentition. Instead, they have structures called baleens formed by alpha-keratin. Nowadays, there are fourteen species in this group kwown as whales and rorquals. Baleen whales feed from fishes, invertebrates like plankton - especially krill crustacean - or benthic invertrebrates. They filter them thanks to a system in which intervene the baleens. Through them, they expulse the ingested water meanwhile they keep the food inside their mouth.