Developing the Full Hormonal Picture

The tally of mammalian hormones extends well beyond the molecules just discussed. What is most puzzling is how the many hormones are interconnected during the control of development. Hormones control gene activities of target cells, and some simple hormone systems act antagonistically (calcitonin-parathormone, insulin-gluca-gon). Yet there has not emerged a clear and complete picture of the overall interactions. Hormones control an incredibly complex array of cellular activities from conception...

American Sign Language Among Primates

Primates are members of the mammalian order Primates, which includes prosimians, or lower primates, and anthropoids (monkeys, apes, and humans). Apes are any primates of the subfamily Hominoidea, including the small apes and the great apes. The gorilla (Gorilla gorilla) is the largest of the great apes. Another great ape is the chimpanzee. The larger member of the chimpanzee family is the common chimpanzee (Pan troglodytes), and the smaller member is the bonobo (Pan paniscus) or the pygmy...

Behavioral and Chemical Research

Both behavioral and chemical techniques are required in order to study pheromones and other semiochemicals. The observation of behavior, either in nature or in captivity, often suggests pheromonal functions. These hypothesized functions are then tested by presenting the pheromone to a potentially responsive organism and observing the response. Situations may be arranged which demand the subject's response to a particular pheromone under otherwise natural conditions. Alternatively, the organisms...

Emergency Veterinary Medicine

Veterinarians dress wounds, inject snake antitoxin and antibiotics, splint broken limbs, and euthanize animals as needed after accidents. Educating clients about possible dangers, veterinarians provide safety information for preemergency preparations for pets and livestock. Veterinarians distribute guides advising how animal owners should respond when faced with natural disasters such as fires, floods, earthquakes, hurricanes, blizzards, and tornados. Other emergencies that can victimize...

Early Zoos and Aquariums

The establishment of the Zoological Society of London's zoological garden at Regent's Park in 1828 was a significant event in the history of animal collecting and may be considered a transition in the evolution of zoos. This collection was intended from its inception to surpass any then in existence, with an emphasis on education and research. Private European menageries evolved into public zoological gardens, going from collections for the few (royalty and wealthy collectors) to zoological...

Maternal Care Versus Paternal Care

In mammals, if only one parent is necessary, it is always the mother who is committed to care-taking because she is the one who must provide the offspring with their first food through nursing. No other animals, however, nurse their young, so in other species, if only one parent is necessary, it does not necessarily have to be the mother who becomes the caretaker. In single-parent species, whether it is the mother or father who becomes the caretaking parent depends, to a great extent, on...

Physical Characteristics of Polar Bears

Male polar bears are up to five feet high at the shoulder while on all fours and up to ten feet long. When standing on its hind legs, a male can be eleven feet tall. Adult males are generally much bigger than females 1,100 to 1,770 pounds for males, 330 to 770 pounds for females. Like other bears, polar bears are plantigrade. Mating takes place in late March to late May. This is the only time that the male is with the female. Other than family groups of females with their cubs, polar bears are...

Studying Kidney Function

The kidney can be studied on many different levels. The output of the kidney, the urine, and the input, the blood, can be analyzed in order to determine function of both kidneys. In some animals, such as the frog, the individual nephrons are visible under a microscope. Through the use of the stop-flow technique, the behavior of an individual portion of the nephron can be studied. In this technique, a very small needle is introduced into one portion of the nephron, and a small drop of oil is...

Chemical Aphrodisiacs

For thousands of years, people have used perfumes, lotions, and oils in an effort to enhance their sexual appeal. Several companies have even started to market chemicals thought to be human phero-mones. Despite the huge appeal of such supposed aphrodisiacs, there is no evidence that any truly work. In other species, however, there exist naturally occurring chemicals that not only signal reproductive readiness, but also affect other individuals' reproductive capacity. In many species, a female...

Digestive System

Testicular Atrophy

The digestive system is composed of the alimentary canal, along with glands such as the liver, salivary glands, and pancreas that produce substances needed in digestion. Digestion starts with the ingestion and chewing of food mixed with saliva. The food passes down the esophagus into the stomach, where the gastric and intestinal juices continue the process. Thereafter, the mixture of food and secretions, called chyme, is pushed down the alimentary canal by peristalsis, rhythmic contractions of...

Evolutionary Development of the Vertebrate Brain

The location of most animals' brain or brainlike organ at the anterior or superior end of the body is important, since it places the brain at the leading end of the moving animal or at its highest point. Many sensory receptors are located in the head, and information from the eyes, ears, and nose can be rapidly received and processed if the processing center is in the same region. In vertebrates, the nervous system is much more advanced than the primitive systems of invertebrates. The...

Centipedes And Millipedes

Types of animal science Anatomy, classification, reproduction Fields of study Anatomy, invertebrate biology, zoology Over twelve thousand species of the arthropods centipedes and millipedes are known. Centipedes are carnivorous, and millipedes are usually vegetarians. diplosomite millipede trunk segment, formed by the fusion of two body segments mandibles jaws of insects and other arthropods nocturnal active at night palp oral sensory organs of arthropods Centipedes and millipedes are somewhat...

Sequestration

Stink Badger Pictures

The production of chemical defenses is often assumed to be expensive because it requires resources that might otherwise have been used for growth and reproduction. One way for a species to avoid such cost is to sequester compounds produced by its prey. Sequestration was first discovered in the monarch butterfly. Monarch caterpillars feed on milkweeds and sequester the plant's cardenolides. Milkweeds produce toxic cardenolides that deter most vertebrate herbivores, but monarchs have evolved the...

Parrots

How Parakeets Lay Eggs Diagram

Parrot species include macaws, cockatoos, true parrots, parakeets, and lories. They are kept as pets for their beautiful coloring and ability to learn to talk. plumage the feathers of birds zygodactyl having two toes pointing backward and two toes pointing forward The hundreds of parrot species are vivid-colored members of the bird family Psitta-cidae. They belong to five classes macaws, cockatoos, true parrots, parakeets, and lories. In parrot plumage, reds and greens often predominate, but...

Pairbonding

How Chimpanzees Mate

Pair-bonding is the formation of attachments or relationships of various durations for purposes of reproduction and care of the young, relationships that may appear analogous to marriage and family in humans. bond, bonding the tie or relationship between opposite-sex partners in a pair bond bonding behaviors behavior patterns that establish, maintain, or strengthen the pair bond consort pair, consortsmp a temporarily bonded pair within a polygamous group long-term pair bond pair bonding that...

Octopus The Master Deceiver

Zebras Predators And Prey

Some animals such as chameleons and anoles, which are mistakenly called chameleons are famous for changing their color to match the background. Anoles can change from whitish to gray, brown, or green to match the sand, branches, or foliage where they rest. Some fish can go one better, creating complex disruptive color patterns to match different kinds of blotchy sand, rock, or coral backgrounds. The master of deception, however, is the octopus. No vertebrate can match the octopus in terms of...

The Human Puzzle

Humans are unusual, but not unique, among mammals in lacking a perceptible estrus period. Did humans, or their hominid ancestors, once have estrus and lose it Is this absence just another oddity in the amazingly wide spectrum of mammalian reproductive traits The fossil record gives no clues, nor are they likely to be found in the future. This silence has not kept anthropologists, etholo-gists, and others from speculating. The prevailing theory until the 1980's asserted that loss of estrus was...

Life Cycle of Chameleons

Exceptions include pygmy stump-tailed chameleons, which are small, ground-living, and lack prehensile tails. Male chameleons are territorial. In many cases, male invaders of a territory are fought actively and the battle ends in the death of one male. In some cases, the combat is ritual, though the male who is faced down leaves. Males and females are solitary, coming together only to mate. Most color changes indicate breeding intentions, pregnancy, or, on the part...

Centipede Facts

Kingdom Animalia Subkingdom Bilateria Phylum Arthropoda Subphylum Uniramia Class Chilopoda Centipedes Families Geophilidae soil centipedes , Litho-biidae stone centipedes , Scolopendridae tropical centipedes , Scutigeridae house centipedes Geographical location Worldwide, in temperate, warm, or tropical regions Habitat Under stones, logs, leaves, other ground litter in human habitations Gestational period Eggs hatch in two to four weeks Life span Six to ten years Special anatomy Sensory...

Tails

Types of animal science Anatomy, evolution, physiology Fields of study Anatomy, conservation biology, developmental biology, entomology, evolutionary science, herpetology, invertebrate biology The tail is a prolongation of the animal body that serves the animal as a means of defense, locomotion, stabilization, or ornament. arboreal living in trees burrowing insectivore an insect-eating animal that usually lives in nests formed by digging holes or tunnels in the ground invertebrate animals...

Theories of Metazoan Origin

Several theories have been proposed to explain the origin of the metazoans. These theories can be placed into the following categories evolution from single-celled protozoans evolution from colonial protozoans evolution from multinucleate coccine cells as a result of development of internal cell boundaries and evolution from sporine cells. There are several versions of each of these theories, and there is no general agreement on which theory is best. Some researchers promote the colonial theory...

Prion and Fungal Diseases

A very unusual kind of infectious pathogen is an abnormal protein called a prion, not associated with either DNAor RNA. Neurodegenerative diseases such as scrapie in sheep and bovine spon-giform encephalopathy BSE, or mad cow disease , as well as kuru and Creutzfeld-Jacob disease in humans, are prion diseases. The abnormal protein is a refolded form of a normal brain protein, and prions cause the normal proteins to fold into the prion form in brains of infected individuals. Prions are very...

Jean Baptiste de Lamarck

Jean Baptiste Lamarck

Born August 1, 1744 Bazentin-le-Petit, Picardy, France Died December 18, 1829 Paris, France Fields of study Evolutionary science, invertebrate biology, paleontology, zoology Contribution Lamarck established the division of animal life into the vertebrate and invertebrate categories, and he formulated an evolutionary theory based on the premise that acquired traits are inheritable. After studying briefly for the priesthood at the Jesuit seminary in Amiens, Jean-Baptiste de Monet, chevalier de...

Seals And Walruses

Type of animal science Classification Fields of study Anatomy, ethology, genetics, marine biology, physiology Essentially aquatic, warm-blooded mammals, seals and though most of them gravitate to the colder areas. against evil carnivores meat-eating animals circumpolar regions the regions around the North and South Poles mollusks a phylum of aquatic invertebrates, usually shelled, such as clams, mussels, and squid muzzle the area around the nose and mouth of an animal pinnipeds web-footed...

The Life Cycle of Marsupials

Marsupials, as mammals, have milk-producing glands and suckle their young. They reproduce similarly to nearly all other mammals One or more eggs, produced internally by the female, are fertilized internally by the male and develop within the female's body. After a period of developmental stages lasting weeks or months, the fertilized egg becomes an embryo, then a fetus, and finally is ready to be born. Marsupials differ because after only a short development period, the young fetus leaves the...

The Hibernation Inducement Trigger

Scientists studying hibernation note that the hibernation inducement trigger HIT springs into action in three specific circumstances, occurring singly or in combination when the days grow shorter in autumn, restricting the amount of light to which organisms are subjected when temperatures drop, which often happens when the days grow shorter and when food becomes scarce. Questions about how HIT works have increased rather than decreased in recent years. Blood extracted from squirrels during...

Skunk Facts

Kingdom Animalia Subkingdom Bilateria Phylum Chordata Subphylum Vertebrata Class Mammalia Order Carnivora Family Mustelidae Subfamily Mephitinae Genus and species Three genera and thirteen species, including Mephitis mephitis striped skunk Spilogale angustifrons southern spotted skunk , S. gracilis western spotted skunk , S. putorius eastern spotted skunk , S. pygmaea pygmy spotted skunk Geographical location The United States, Mexico, southern Canada, and Central America Habitat Rocky crevices...

Endocrine Control of Pregnancy Parturition and Lactation

During an ovarian cycle, a pregnancy can occur if the ovum becomes fertilized. The events that occur during pregnancy are also controlled by hormones. In mammals, fertilization normally occurs in the oviduct. When the fertilized embryo is implanted in the uterus, it is nourished as a result of the glandular and vascular buildup of the uterine wall. This buildup is maintained by estrogen and progesterone secreted by the corpus luteum. As the embryo grows, it begins to produce a portion of the...

New World Platyrrhine Monkeys

New World Monkeys

The New World monkeys are a highly successful and diversified group colonizing Central and South America. The term usually refers to the infraorder Platyrrhini, meaning flat-nosed. As compared with the Catarrhine monkeys, the nostrils of the Platyrrhines are broadly separated and usually point to the sides. Members of the Platyrrhines include capuchins, howler monkeys, sakis, woolly monkeys, squirrel monkeys, and uakaris, a total of about forty-five species. New World monkeys have long, thin...

Tasmanian Devils

1941 Picture Tasmanian Devil

The Tasmanian devil is the world's largest carnivorous marsupial. It is now found only on the island of Tasmania, where it is reasonably common throughout the island and is strictly protected. Its noisy and screechy sounds make it seem much more ferocious than its size might indicate. adaptive radiation the process by which many species evolve from a single ancestral species in adapting to new habitats dingo the wild dog brought to Australia by the aborigines marsupial primitive mammals in...

Migration and Eating Habits

All antelope are herbivores vegetarians . They usually travel slowly within the security of their herds. Because of their numbers, they can anticipate danger as they travel and avoid it when it is imminent. As they move through their habitats, some species, such as the wildebeest also called the gnu , graze on the grass of the savannas in which they usually live. Species whose habitat is in forests tend to eat the leaves and slender branches of trees, often standing on their hind legs to reach...

Ichthyosaur Facts

Kingdom Animalia Phylum Chordata Subphylum Craniata Class Reptilia Subclass Lepidosauria Order Ichthyopterygia Family Ophthalmosauria Genus and species Ophthalmosaurus icenicus Geographical location Oceans of the Mesozoic Era Habitat Marine Gestational period Unknown Life span Unknown Special anatomy Limbs transformed to flippers wings that employ hyperphalangy to elongate flipper reevolve dorsal fin and tail fluke in some smooth skin without scales rostrum elongate with conical labyrinthodont...

Dog Wolf and Coyote Facts

Wolves Natural Habitat

Kingdom Animalia Subkingdom Metazoa Phylum Chordata Subphylum Vertebrata Class Mammalia Subclass Eutheria Order Carnivora Suborder Canoidea Family Canidae Genus and species Ten genera and thirty-five species, including Canis familiaris domestic dog , C. lupus gray wolf , C. rufus red wolf , C. latrans coyote Geographical location Dogs live on every continent except Antarctica wolves are not found in Africa, South America, and Australia coyotes live only in North and Central America Habitat...

Chameleon Facts

Family Chamaeleontidae chameleons Genera Chamaleo twenty-four species , Brookesia four subgenera, eight species Geographical location Madagascar, Africa, Asia, and Europe Habitat Land-dwellers mostly arboreal, though some live on the ground Gestational period Females lay ten to sixty fertilized eggs, which hatch on their own Life span Five to ten years Special anatomy Eyes that rotate 360 degrees, zygodactyl feet, prehensile tails, spearlike horns for mating and combat, long sticky tongues...

Porcupine Life Cycle

Adult porcupines are solitary mammals for most of the year, except during the breeding season, between September and November. Female porcupines begin reproductive activities at about 1.5 years of age. It is common to find several males around a female during her brief eight- to twelve-hour time of receptivity. Mating is brief and occurs on the ground, with the female raising her tail over her back. After the male has inseminated her, each porcupine goes its separate way. Usually only one...

Natural Selection In Snowy Owls

Pygmy Owl Catching Prey

Any of the Strigiformes, a group of birds with highly specialized characteristics for nocturnal activity, including soft feathers and enhanced hearing and eyesight. asymmetrical ears in some species of owls, the ears are of unequal size and located unequally on the sides of the head asynchronous an uneven event in hawks and owls, the staggered hatching of eggs that results in a nest of different-aged young facial disk the distinctive concentric circles of feathers that encircle the eyes of...

Seahorses

Seahorse Species

At least thirty-five species of seahorses, classified in the genus of Hippocampus, live in shallow subtropical coastal areas around the world. They swim in an upright position and have a head suggestive of a horse, a prickly looking body, and a prehensile tail. The male incubates eggs in a pouch in its abdomen and gives birth to live young. dorsal fin fin on the back of a fish ovipositor a tube that extends from the female's body for depositing eggs pectoral fin one of a pair of fins just...

Factors Affecting Metabolic Rate

One of the most important factors that affects metabolic rate is the temperature of the organism, since within limits all chemical reactions of metabolism proceed faster at higher temperatures. The internal temperature of most invertebrate an imals, fish, and amphibians is the same as the temperature of the environment in which they live. Such organisms are called poikilotherms. In poikilothermic organisms, metabolic rate increases as the environmental temperature increases. Such organisms move...

Armadillos Anteaters And Sloths

Type of animal science Classification Fields of study Anatomy, physiology, zoology Anteaters, armadillos, and sloths belong to the order Edentata without teeth . The order includes the giant ant-eater and three smaller anteaters, two genera of sloths, and eight genera consisting of twenty species ofarmadillos. arboreal living in trees herbivorous plant-eating nocturnal active only at night Anteaters, armadillos, sloths, and several extinct species make up an order of mammals called Edentata...

Chickens Turkeys Pheasant And Quail

Type of animal science Classification Fields of study Anatomy, zoology The chicken, turkey, pheasant, and quail are related members of the family Phasianidae. Chickens are probably the most numerous bird in the world. chicks baby birds from chickens, turkeys, pheasant, or quail clutch a group of eggs in a nest cock male chicken, pheasant, or quail cockerel young male chicken, pheasant, egg a round, hard-shelled object produced by the female bird that may produce offspring, but is often used as...

Chameleons

Types of animal science Anatomy, classification, reproduction Fields of study Anatomy, zoology Chameleons, the family Chamaeleontidae, have long, sticky tongues to capture prey. Other unique characteristics include eyes that operate independently of each other, leaflike body shapes, ability to change skin color, zygodactyly, and prehensile tails. arboreal dwelling in trees chromatophore a color-causing cell cold-blooded animals whose body temperatures equal the temperature of their surroundings...

Physical Characteristics of Reindeer

Reindeer differ from most deer in having large, deeply cleft hooves, hairy muzzles to help to keep them warm, and antlers on both males and females. Reindeer have long bodies and legs. Their hooves are broad, to provide footing on snow and ice. Male reindeer are four feet tall at shoulder height and weigh up to six hundred pounds. Females are shorter but reach similar maximum weights. Both genders grow up to seven feet long. Their thick, waterproof fur is brown in summer and gray-brown in...

Jaguars

Jaguars are the largest cats found in North or South America, originally occupying a wide diversity of habitats from the southwestern United States to Patagonia. vibrissae stiff hairs, projecting as feelers from nose and head Among big cats, jaguars, much larger than leopards, are exceeded in size only by lions and tigers. Males weigh from 125 to 250 pounds, are 6 to 9 feet long including a tail up to 2.5 feet long , and stand twenty-four to thirty inches tall at the shoulder females tend to be...

Physical Characteristics of Kangaroos

Bare Teats

Kangaroos stand on large rear legs, using their long tail for added support. They have small front legs, with handlike paws that lack an opposable thumb. Hopping is their most unusual characteristic. Besides kangaroos and their relatives, no vertebrate bigger than ten pounds hops. At slow speeds, kangaroos walk awkwardly and inefficiently, using their front legs and tail. However, at speeds over fifteen miles per hour, they hop upright in a graceful motion that can be more energetically...

The Life Cycle of Hyenas

Hyena Life Cycle

There are similarities and differences in hyena species lives. Spotted hyenas form groups of up to The spotted hyena's maniacal, eerie cry has led to it being called the laughing hyena. Digital Stock one hundred a few males, many females, and numerous young. Females conceive year round, birthing two or three pups that can see and run immediately, after a four-month gestation. Females, larger than males, select short-term mates. Striped hyenas fight within groups, sometimes killing group...

Termites

Termites are cellulose-eating social insects that live in colonies of hundreds to millions of individual members produced by a single king and queen. Termites are highly beneficial to the ecosystem because they break down dead plant material, but some species can become serious pests when they colonize manmade wooden structures. alates recently molted winged adult termites carton cardboardlike material composed of wood fragments, saliva, and fecal matter, used for constructing termite nests...