Blind Trading: A Literature Review of Research Addressing the Welfare of Ball Pythons in the Exotic Pet Trade

Simple Summary The Ball python is a small species that is commonly kept as an exotic pet across the world. Despite huge numbers of these snakes being kept and traded in the pet industry, there is very little information available about how catching, breeding, transporting and housing them in captivity could impact their welfare. Our study reviewed the published literature for this species and found 88 relevant peer-reviewed scientific papers. Physical health was the predominant focus of research, with numerous studies reporting on disease, injury or clinical treatments. Far fewer papers focused on other aspects of Ball python wellbeing, including behaviour, nutrition, environment or mental condition. We also found that very few studies focused on wellbeing prior to pet ownership, i.e., during the early stages of the trade chain when they are caught from the wild, transported, or bred in captivity. We recommend that more research is needed to assess the impact of the exotic pet trade on this species’ welfare. In particular, research on welfare conditions during capture and transportation of wild Ball pythons, and the potential effects of captive breeding, could help reduce suffering throughout the trade. Abstract Extensive numbers of Ball pythons are caught, bred, traded and subsequently kept in captivity across the world as part of the exotic pet industry. Despite their widespread availability as pets, relatively little is known about the potential welfare challenges affecting them. We reviewed the literature for research focused on the health and welfare of Ball pythons in the international pet trade. From a total of 88 articles returned from the search criteria, our analysis showed that very few actually focused on trade (10%) or animal welfare (17%). Instead, the majority (64%) of articles focused on veterinary science. There was a considerable bias towards physical health, with most studies neglecting the four other domains of animal welfare (behaviour, nutrition, environment and mental health). Furthermore, very few studies considered Ball pythons prior to resulting pet ownership, during wild capture and transportation or captive breeding operations. Our review demonstrates that our current understanding of welfare for Ball pythons traded as exotic pets is limited. We recommend that future research should focus on aspects of the industry that are currently overlooked, including the potential consequences of genetic selection during captive-breeding and the conditions provided for snakes prior to and during international transportation.


Health
Definition Hyperglycaemia An excess of sugar in the blood Anemia Condition in which the blood is deficient in red blood cells, in hemoglobin, or in total volume Azurophilia No definition given Bacterial infection (unspecified) No definition Bbilateral corneal opacity Bilateral : of, relating to, or affecting the right and left sides of the body or the right and left members of paired organs Cornea : the transparent part of the coat of the eyeball that covers the iris and pupil and admits light to the interior An act of regurgitating such as a: the casting up of incompletely digested food (as by some birds in feeding their young) b : the backward flow of blood through a defective heart valve Stargazing The quality or state of being absentminded Opacity : an opaque spot in a normally transparent structure (as the lens of the eye) Bilateral corneal ulceration Ulcer 1: a break in skin or mucous membrane with loss of surface tissue, disintegration and necrosis of epithelial tissue, and often pus 2: something that festers and corrupts like an open sore Bronchial epithelial hyperplasia Bronchial : of or relating to the bronchi or their ramifications in the lungs Bronchus : either of the two primary divisions of the trachea that lead respectively into the right and the left lung Epithelium : a membranous cellular tissue that covers a free surface or lines a tube or cavity of an animal body and serves especially to enclose and protect the other parts of the body, to produce secretions and excretions, and to function in assimilation Hyperplasia : an abnormal or unusual increase in the elements composing a part (as cells composing a tissue)

Cardiac malformations
Cardiac (Entry 1 of 2) a: of, relating to, situated near, or acting on the heart b: of or relating to the cardia of the stomach Malformation : irregular, anomalous, abnormal, or faulty formation or structure Caudal paralysis Caudal 1: of, relating to, or being a tail 2: situated in or directed toward the hind part of the body Paralysis : complete or partial loss of function especially when involving the power of motion or of sensation in any part of the body Central nervous system disease Central nervous system : the part of the nervous system which in vertebrates consists of the brain and spinal cord, to which sensory impulses are transmitted and from which motor impulses pass out, and which supervises and coordinates the activity of the entire nervous system Disease : an impairment of the normal state of the living animal or plant body or one of its parts that interrupts or modifies the performance of the vital functions, is typically manifested by distinguishing signs and symptoms, and is a response to environmental factors (as malnutrition, industrial hazards, or climate), to specific infective agents (as worms, bacteria, or viruses), to inherent defects of the organism (as genetic anomalies), or to combinations of these factors : sickness, illness Gastrointestinal : of, relating to, or affecting both stomach and intestine Tract : a system of body parts or organs that act together to perform some function Disease : an impairment of the normal state of the living animal or plant body or one of its parts that interrupts or modifies the performance of the vital functions, is typically manifested by distinguishing signs and symptoms, and is a response to environmental factors (as malnutrition, industrial hazards, or climate), to specific infective agents (as worms, bacteria, or viruses), to inherent defects of the organism (as genetic anomalies), or to combinations of these factors : sickness, illness

Granulocytic meningomyelitis
Granulocyte : any of a group of white blood cells (as a basophil, eosinophil, or neutrophil) characterized by granule-containing cytoplasm and a usually lobed nucleus Meningomyelitis : inflammation of the spinal cord and its enveloping membranes Hamartoma A mass resembling a tumor that represents anomalous development of tissue natural to a part or organ rather than a true tumor Hepatic lipidosis Hepatic : of, relating to, affecting, or associated with the liver Lipidosis : a disorder of fat metabolism especially involving the deposition of fat in an organ (as the liver or spleen) Heteropenia No definition Moderate heterophilic and lymphocytic anterior uveitis Heterophile : of, relating to, or being an antibody circulating in blood serum that is reactive with antigen originating in a different species Lymphocyte : any of the colorless weakly motile cells that originate from stem cells and differentiate in lymphoid tissue (as of the thymus or bone marrow), that are the typical cellular elements of lymph, that include the cellular mediators of immunity, and that constitute 20 to 30 % of the white blood cells of normal human blood Anterior : relating to or situated near or toward the head or toward the part in headless animals most nearly corresponding to the head Uveitis : inflammation of the uvea Heterophilic and lymphocytic keratoconjunctivitis with neovascularization and intralesional bacterial colonies Heterophile : of, relating to, or being an antibody circulating in blood serum that is reactive with antigen originating in a different species Lymphocyte : any of the colorless weakly motile cells that originate from stem cells and differentiate in lymphoid tissue (as of the thymus or bone marrow), that are the typical cellular elements of lymph, that include the cellular mediators of immunity, and that constitute 20 to 30 % of the white blood cells of normal human blood Keratoconjunctivitis : combined inflammation of the cornea and conjunctiva Neovascularization : vascularization especially in abnormal quantity (as in some conditions of the retina) or in abnormal tissue (as a tumor) Intralesional : introduced into or performed within a lesion Bacterial : of, relating to, or caused by bacteria Colony : a circumscribed mass of microorganisms usually growing in or on a solid medium Histiocytic meningomyelitis Histiocytic : of, relating to, or containing macrophages Meningomyelitis : inflammation of the spinal cord and its enveloping membranes

Hyperplasia
An abnormal or unusual increase in the elements composing a part (as cells composing a tissue) Hyperuricacidaemia No definition

Leptospirosis
Any of several diseases of humans and domestic animals (as cattle and dogs) that are caused by infection with spirochetes of the genus Leptospira

Lesions
An abnormal change in structure of an organ or part due to injury or disease especially one that is circumscribed and well defined

Leukocytosis
An increase in the number of white blood cells in the circulating blood that occurs normally (as after meals) or abnormally (as in some infections)

Lymphocytic biliary dochitis
Lymphocyte : any of the colorless weakly motile cells that originate from stem cells and differentiate in lymphoid tissue (as of the thymus or bone marrow), that are the typical cellular elements of lymph, that include the cellular mediators of immunity, and that constitute 20 to 30 % of the white blood cells of normal human blood Biliary : of, relating to, or conveying bile No definition for dochitis

Lymphocytic encephalitis
Lymphocyte : any of the colorless weakly motile cells that originate from stem cells and differentiate in lymphoid tissue (as of the thymus or bone marrow), that are the typical cellular elements of lymph, that include the cellular mediators of immunity, and that constitute 20 to 30 % of the white blood cells of normal human blood Encephalitis : inflammation of the brain that is caused especially by infection with a virus (such as herpes simplex, varicella zoster, or West Nile virus) or less commonly by bacterial or fungal infection or autoimmune reaction An acute disease that is marked by inflammation of lung tissue accompanied by infiltration of alveoli and often bronchioles with white blood cells (as neutrophils) and fibrinous exudate, is characterized by fever, chills, cough, difficulty in breathing, fatigue, chest pain, and reduced lung expansion, and is typically caused by an infectious agent (as a bacterium, virus, or fungus)

Pulmonary haemorrhage
Pulmonary : relating to, functioning like, associated with, or carried on by the lungs Haemorrhage : a copious discharge of blood from the blood vessels

Renal lesions
Renal : relating to, involving, affecting, or located in the region of the kidney Lesion : an abnormal change in structure of an organ or part due to injury or disease especially one that is circumscribed and well defined

Renal tubular degeneration
Renal : relating to, involving, affecting, or located in the region of the kidney Tubular 1: having the form of or consisting of a tube 2: of, relating to, or sounding as if produced through a tube or tubule Degeneration 1: intellectual or moral decline tending toward dissolution of character or integrity: a progressive worsening of personal adjustment 2a: progressive deterioration of physical characters from a level representing the norm of earlier generations or forms: regression of the morphology of a group or kind of organism toward a simpler less highly organized state parasitism leads to degeneration 2b: deterioration of a tissue or an organ in which its vitality is diminished or its structure impaired : of or relating to dermatology Dermatology : a branch of medicine dealing with the skin and its structure, functions, and diseases Lesion : an abnormal change in structure of an organ or part due to injury or disease especially one that is circumscribed and well defined Inflammation A local response to cellular injury that is marked by capillary dilatation, leukocytic infiltration, redness, heat, pain, swelling, and often loss of function and that serves as a mechanism initiating the elimination of noxious agents and of damaged tissue Skin incision A cut or wound of body tissue made especially in surgery Table S3. Definition of terms (bacteria).

Acinetobacter lwoffii
Acinetobacter 1: a genus of nonmotile, gram-negative bacteria (family Moraxellaceae) that are short rods typically growing in pairs or in chains, that occur in soil and water, and that are associated with opportunistic infections especially of the skin, lungs, and urinary tract 2: a bacterium of the genus Acinetobacter No definition for lwoffii Aeromonas hydrophila No definition

Anaplasma phagocytophilum
Anaplasma : a genus of parasitic, gram-negative, nonmotile bacteria of the family Anaplasmataceae that are transmitted chiefly by ticks and biting flies and infect the red blood cells of humans and animals No definition for phagocytophilum

Bacteroides spp.
A genus of gram-negative anaerobic bacteria that belong to the family Bacteroidaceae, that have rounded ends, produce no endospores and no pigment, and that occur usually in the normal intestinal flora

Bordetella hinzii
A genus of bacteria comprising very short gram-negative strictly aerobic coccuslike bacilli and including the causative agent (B. pertussis) of whooping cough Chlamydophilosis No definition

Citrobacter freundii
No definition

Clostridium spp.
A genus of saprophytic rod-shaped or spindle-shaped usually gram-positive bacteria (family Clostridiaceae) that are anaerobic or require very little free oxygen and are nearly cosmopolitan in soil, water, sewage, and animal and human intestines, that are very active biochemically comprising numerous fermenters of carbohydrates with vigorous production of acid and gas, many nitrogen-fixers, and others which rapidly putrefy proteins, and that include important pathogens Elizabethkingia meningoseptica No definition

Enterobacter cloacae
Enterobacter : a genus of aerobic gram-negative bacteria of the family Enterobacteriaceae that produce acid and gas from many sugars (as dextrose and lactose), form acetoin, are widely distributed in nature (as in feces, soil, water, and the contents of human and animal intestines), and include some that may be pathogenic Cloaca : the common chamber into which the intestinal, urinary, and generative canals discharge especially in monotreme mammals, birds, reptiles, amphibians, and elasmobranch fishes

Enterococcus pallens
Enterococcus : any of a genus (Enterococcus) of gram-positive bacteria that resemble streptococci and were formerly classified with them especially a bacterium (E. faecalis) normally present in the intestine No definition for pallens

Escherichia coli
Escherichia : a genus of aerobic gram-negative rod-shaped bacteria of the family Enterobacteriaceae that form acid and gas on many carbohydrates (as dextrose and lactose) but no acetoin and that include occasionally pathogenic forms (as some strains of E. coli) normally present in the human intestine and other forms which typically occur in soil and water Coli (Entry 1 of 2) : of or relating to bacteria normally inhabiting the intestine or colon and especially to species of the genus Escherichia (  the type genus of the family Trypanosomatidae comprising kinetoplastid flagellates that as adults are elongated and somewhat spindle-shaped, have a posteriorly arising flagellum which passes forward at the margin of an undulating membrane and emerges near the anterior end of the body as a short free flagellum, and are parasitic in the blood or rarely the tissues of vertebrates, that following development in the digestive tract of a blood-sucking invertebrate and usually an insect pass ultimately to the mouthparts or salivary structures where they may be transmitted into a new vertebrate host bitten by the invertebrate host, and that are responsible for various serious diseases (as Chagas disease, dourine, nagana, sleeping sickness, and surra) of humans and domestic animals