Spider Morph - A Cruel Human Made Disaster?
- Scott Lockhart
- Dec 12, 2025
- 6 min read
Updated: Feb 18
The appeal to breed the most designer Ball Python offspring must sound like a lucrative and fascinating venture but can it be deemed unethical once we see the outcome.
Ball Pythons, like all wild animals, were initially difficult to care due to limited research and lack-of supply before the1970s. Once us humans knew how to tame them and breed them in captivity, they would come to be one of the most commonly kept species in the Herptile community.
They can range in all colours, emotions and sizes (adults reach 5 feet long). Most are friendly in captive care and could be recommended as the go-to starter reptile for beginners. As with all Herptiles though, they need enough space to manoeuvre themselves around and plenty of hides/plants to make them feel safe and secure. The temperatures on the basking side are in the low 30's °C and humidity at highs of 80%.
Where did it all start?
Kevin McCurley, New England Reptile Distributors in Massachussetts, America, brought the genetic mutation to prominence in 1999. Morphmarket wrote on their website that Kevin imported "two animals that looked extremely similar and initially called both of them 'Woma Tiger'.
As Kevin started breeding these two different animals, he noticed that they behaved a little bit differently from one another. He then bred both of them to a Lesser and got the SoulSucker from one and the much less interesting Lesser Woma from the other.
At that point NERD decided that they were different morphs and that the one that produced the SoulSucker had some other gene" (Spider) " 'hidden' inside of it. To differentiate between them he started calling one line 'Hidden Gene Woma' and the other line he just kept as 'Woma Tiger'. Eventually, the 'Tiger' was dropped from the name."
The weird behaviour that he noticed would possibly be the 'wobbles' and other peculiar neurological movements. This would severely casual movement and strike accuracy. Their survival would be at stake. Unfortunately, it started a tidal wave of genetic Frankenstein creations among captive breeders.
Research goes a long way
Elfring et al. wrote in a study from 2024 that the "Spider morph in ball pythons is a pattern anomaly characterised by a reduction in pattern and dark melanin pigmentation. It is also associated with pleiotropy, as Spider morph individuals frequently display abnormal head movements, a syndrome known as ‘the wobble’, which has been linked to malformations of the sacculus and the semicircular canals (Starck et al. 2022)."
Despite the controversy of its impact on the trade, Kevin regards it as his favourite morph and recommends this gene pool for a new breeder in an interview by World of Ball Pythons in 2012.
For
This is where the waters get muddy. Experts in the field of Herpetology are torn between the positive and negative aspects of the gene. On one hand, there are opinions of how cool the morph looks and the effects are not as bad as they seem with most genotypes living a relatively problem-free life.
We can compare this mutation to other animals such as dogs, who have been genetically modified by us humans. Therefore, a breeder should be allowed to distribute the spider morph without condemnation from the community as it is not an illegal act.
Some may debate whether it is a predominantly human-made problem as there have been wild-caught specimens that portray the spider gene already. If any snakes have this 'health problem' then it can be easily managed in captivity.
Against
Conversely, there is evidence to show the outcome of such breeding is worse than first realised. Conservationist student and Zoologist graduate Shannon Casey kindly spoke to me regarding this issue:
"I think from a welfare standpoint, I strongly oppose the breeding of the spider morph in ball pythons. Because neurological issues associated with the spider gene like the wobble syndrome, is inseparable from the phenotype, rather than a husbandry issue it cannot just be mitigated through care which i believe raises concerns about knowingly producing animals with heritable welfare conditions which in severe cases can be lethal.
Also the recent demand for designer morphs seems to prioritise visual aesthetics rather than the wellbeing of the animals. In my view, the reptile community need to recognise that an aesthetic preference should NEVER override an animals quality of life. The spider morph is a clear example of a gene where the welfare cost is well documented, consistent and honestly just completely unethical to justify continuing to produce and sell these animals.
In all honesty I can’t really think of many positives when it comes to the spider gene, other than it possibly being a valuable educational opportunity, it has highlighted how a “visually appealing” mutation can genetically lead to significant neurological issues, making it an important example for teaching herpetological genetics, developmental biology and the ethical boundaries surrounding selective breeding."
She goes on to say "I do believe the comparison to brachycephalic dogs is an interesting angle, and I can totally see why some breeders might use it as an argument. Personally though, I actually hold the same welfare concerns for breeding brachycephalic dogs and other breeds with genetic issues as I do for breeding spider morph pythons, I think if we are knowingly producing animals with traits that compromise an animals welfare, we’ve crossed a line regardless whether that species is a dog or snake
Also, attitudes and legislation around brachycephalic dogs are changing rapidly in the uk and internationally. In the UK current guidance suggest that breeding animals with extreme traits that cause welfare problems may breach existing welfare laws (such as the animal welfare act 2006) also countries like Norway and the Netherlands have already moved to ban the breeding of certain brachycephalic dogs entirely, as well as other breeds like the cavalier King Charles spaniel who suffer from neurological issues (like the spider morph) such as syringomyelia, so if anything, the dog breeding example actually strengthens the argument that breeding animals with harmful inherited traits is becoming socially AND legally unacceptable
There’s also an important distinction, in dogs, traits like extreme short muzzles can in theory be bred backwards towards a healthier skull shape over generations. With the spider morph however, the neurological issues are directly tied to the phenotype and cannot be separated from the gene itself.
I believe you are right that the first known snakes with the spider gene were wild caught, however I’m still not sure that strengthens the pro spider morph argument. In the wild natural selection would act against individuals with traits associated with the spider morph (coordination problems, disorientation and impaired prey response) so these traits would not persist well in a natural population.
Additionally, given that the entire morph stems from a very small founder population, it can be questioned whether inbreeding could be intensifying the severity of neurological issues we see today."
Matthias Starck et al. noted in 2022 that "All spider morph snakes showed the wobble condition (i.e., twisting movements of the head, impaired locomotion, difficulty striking or constricting prey items).
We describe the inner ear structures in wild-type and spider morph snakes and report a deviant morphology of semicircular canals, ampullae and sacculus in the latter.
We also report about associated differences in the desmal skull bones of spider morph snakes, which were characterized by wider semicircular canals, ampullae widened and difficult to discern in μCT, a deformed crus communis, and a small sacculus with a highly deviant X-ray morphology as compared to wildtype individuals."
Evidently, there are more problems than solutions. Contributing to the genotype's outbreak is detrimental to the herptile world and should be an immoral crippling weight to bear if doing so. In the future there may be an imperative notion to introduce legislation to ban the production and distribution of this particular morph.
Bibliography
Garcia‐Elfring, A., Roffey, H.L., Abergas, J.M., Jurgen Wuyts, Hendry, A.P., Tzika, A.C. and Barrett (2024). A Ball Python Colour Morph Implicates MC1R in Melanophore–Xanthophore Distribution and Pattern Formation. Pigment Cell & Melanoma Research. doi:https://doi.org/10.1111/pcmr.13215.
Starck, J.M., Schrenk, F., Schröder, S. and Pees, M. (2022). Malformations of the sacculus and the semicircular canals in spider morph pythons. PLOS ONE, 17(8), p.e0262788. doi:https://doi.org/10.1371/journal.pone.0262788.
World of Ball Pythons. (2012). Articles - World of Ball Pythons. [online] Available at: https://www.worldofballpythons.com/articles/breeder-interview-kevin-mccurley/ [Accessed 28 Nov. 2025].
Animal Welfare Act 2006, c. 45. Available at: https://www.legislation.gov.uk/ukpga/2006/45
British Veterinary Association (BVA). (no date) Extreme conformation. Available at: https://www.bva.co.uk/take-action/our-policies/extreme-conformation/
Eurogroup for Animals. (2023) Extreme breeding in Europe: mapping of legislation. Available at:
Eurogroup for Animals. (2023) Landmark ruling against unethical dog breeding – Norway. Available at:
Youens, E., O’Neill, D. G., Belshaw, Z., Mochizuki, S., Neufuss, J., Tivers, M. S. & Packer, R. M. A. (2025) ‘Beauty versus the beast: The UK public prefers less-extreme body shapes in brachycephalic dog breeds’, Veterinary Record, 197(6), e5671. doi: 10.1002/vetr.5671.
Comments