Although oviparous vertebrate species have specific incubation periods, environmental factors, such as higher or lower temperatures, can interfere in the incubation period of an animal. Higher-than-average temperatures tend to shorten the incubation period of most species. The royal albatross incubates a single egg for about 80 days, while the emperor penguin takes seven to eight weeks to incubate its egg. Smaller birds often have shorter incubation periods, which can last for up to 20 days. In most turtle species, the incubation period lasts from 45 to 70 days. The incubation period of the Eastern American toad can vary from three to 12 days.
Most invertebrate animals, such as insects, spiders, crustaceans and mollusks, reproduce through eggs. Like vertebrates, invertebrates also have different incubation periods. The incubation period of the spider crab ranges from three months, at 46.4 degrees Fahrenheit, to seven days, at 78.8 degrees Fahrenheit. Although females of some species of crayfish and spiders can keep the eggs on their abdomen during the incubation period, most invertebrates do not look after their eggs during this time.
Bacteria can cause serious diseases, such as pneumonia, typhoid fever, tetanus, syphilis, cholera, leprosy and tuberculosis. Incubation periods of pathogenic bacteria vary according to the dose of exposure and the general health condition of the exposed person. While salmonella and other bacteria that cause food poisoning can have incubation periods shorter than 24 hours, the incubation period for syphilis can last from one week to more than two months, and up to five years in the case of leprosy.
Like in bacterial diseases, the incubation period for virus-related diseases can vary according to virus type and other factors. The HIV virus has one of the longest incubation periods, lasting for up to 15 years. Hepatitis A can have an incubation period of up to 50 days, while for rabies, the incubation period can be as long as one year. Diseases with shorter incubation periods include the common cold, dengue hemorrhagic fever and cold sores or herpes, with an average of 10 hours.