Egg binding occurs in animals, such as reptiles or birds, when an

egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the ...

takes longer than usual to pass out of the reproductive tract.

In birds

In birds, egg binding may be caused by obesity, nutritional imbalances such as calcium deficiency, environmental stress such as temperature changes, or malformed eggs. The egg may be stuck near the

cloaca A cloaca ( ), : cloacae ( or ), or vent, is the rear orifice that serves as the only opening for the digestive (rectum), reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles, birds, cartilagin ...

, or further inside. Egg binding is a reasonably common, and potentially serious condition that can lead to infection or damage to internal tissue. The bound egg may be gently massaged out; failing this it may become necessary to break the egg ''

in situ is a Latin phrase meaning 'in place' or 'on site', derived from ' ('in') and ' ( ablative of ''situs'', ). The term typically refers to the examination or occurrence of a process within its original context, without relocation. The term is use ...

'' and remove it in parts. If broken, the

oviduct The oviduct in vertebrates is the passageway from an ovary. In human females, this is more usually known as the fallopian tube. The eggs travel along the oviduct. These eggs will either be fertilized by spermatozoa to become a zygote, or will dege ...

should be cleaned of shell fragments and egg residue to avoid damage or infection.

In reptiles

In reptiles, it is inadvisable to attempt to break a reptile egg to remove it from an egg-bound female. This procedure may be done by a veterinarian, who will insert a needle into the egg, and withdraw the contents with a syringe, allowing the egg to collapse and be removed. Non-surgical interventions include administering

oxytocin Oxytocin is a peptide hormone and neuropeptide normally produced in the hypothalamus and released by the posterior pituitary. Present in animals since early stages of evolution, in humans it plays roles in behavior that include Human bonding, ...

to improve contractions and allow the egg(s) to pass normally. In many cases, egg-bound reptiles must undergo surgery to have stuck eggs removed. Egg binding in reptiles is quickly fatal if left untreated; therefore, gravid females who become very lethargic and cease feeding need immediate medical treatment in order to treat the potentially life-threatening condition. Egg binding can occur if an egg is malformed and/or too large, the animal is weakened by illness, improper

husbandry Animal husbandry is the branch of agriculture concerned with animals that are raised for meat, fibre, milk, or other products. It includes day-to-day care, management, production, nutrition, selective breeding, and the raising of livestock. ...

, stress, or if hormonal balances are wrong (producing weak contractions). Factors that can contribute to the risk of egg binding include calcium deficiency, breeding animals that are too young or too small, not providing suitable laying areas (leading to deliberate retention of eggs), and overfeeding of species in which clutch size is dependent on food intake, such as the

veiled chameleon The veiled chameleon (''Chamaeleo calyptratus'') is a species of chameleon (family Chamaeleonidae) native to the Arabian Peninsula in Yemen and Saudi Arabia. Other common names include cone-head chameleon, Yemen chameleon, and Yemeni chameleon. ...

. In the context of

behavioral ecology Behavioral ecology, also spelled behavioural ecology, is the study of the evolutionary basis for ethology, animal behavior due to ecology, ecological pressures. Behavioral ecology emerged from ethology after Niko Tinbergen outlined Tinbergen's f ...

, egg binding can be an important factor in limiting clutch size. Lizards that lay fewer, but larger eggs are at higher risk for egg binding, and so there is selection pressure towards a minimum clutch size. For example, in common side-blotched lizards, females that lay fewer than the average 4–5 eggs per clutch have significantly increased risk of egg binding.

In popular culture

* An episode of the

Animal Planet Animal Planet (stylized in all lowercase since 2018) is an American multinational pay television channel focusing on the animal kingdom owned by the Warner Bros. Discovery Networks unit of Warner Bros. Discovery. First established on June 1 ...

reality show Reality television is a genre of television programming that documents purportedly unscripted real-life situations, often starring ordinary people rather than professional actors. Reality television emerged as a distinct genre in the early 1990s ...

'' E-Vet Interns'' featured the treatment of an egg-bound turtle named Napoleon. * An episode of

Netflix Netflix is an American subscription video on-demand over-the-top streaming service. The service primarily distributes original and acquired films and television shows from various genres, and it is available internationally in multiple lang ...

animated show '' Tuca & Bertie'', "Yeast Week," featured main character Tuca going to the doctor and undergoing surgery because she is egg-bound. * Bumpy, an

Ankylosaurus ''Ankylosaurus'' is a genus of Thyreophora, armored dinosaur. Its fossils have been found in geological formations dating to the very end of the Cretaceous Period (geology), Period, about 68–66 million years ago, in western North America, m ...

character from the animated show Jurassic World: Chaos Theory was egg-bound.

References

External links

{{Wiktionary, binding
Advice from "Fowl Play" which describes how to diagnose and treat egg binding in hens
(via archive.org)
Egg Bound Chicken – Symptoms and Treatment
Bird breeding Bird diseases Reptile diseases Poultry diseases Poultry farming