Two cats from Pennsylvania have captivated the internet due to their strikingly different appearances. River and Elsa, who are siblings from the same litter, were brought into the spotlight when their owner, Dylan, posted a picture of them on Reddit. In his post, Dylan asked the online community why his cats looked so different. The question sparked a variety of theories and explanations.

Many Reddit users suggested that genetics played a role in the cats' differing appearances. One user humorously admitted their lack of knowledge, commenting, "Genetics and stuff? I failed chemistry and biology, so that's all I can contribute.

" Another user with a background in biology explained that the cats' appearances were a result of "mix-and-match genetics." Several users shared their own experiences of cats from the same litter looking vastly different.

Some responses took a more humorous approach. One person playfully suggested that a cat nurse had swapped the babies at the clinic, while another joked about replacing one of the kittens with a fake when they were younger. One Redditor commented on cats' notorious independence, stating, "Cats don't even obey their own DNA."

The most likely explanation for River and Elsa's differing looks is a phenomenon called "heteropaternal superfecundation.

" This occurs when a female cat is impregnated by multiple males during a single ovulation period, resulting in kittens with different genetic makeups. While rare in humans, heteropaternal superfecundation is not uncommon in cats.

The unique reproductive characteristics of felines contribute to the prevalence of this phenomenon. Cats, being "seasonally polyestrous," have multiple reproductive cycles during the breeding season, which increases the likelihood of multiple paternity.

While different fathers are the most likely explanation for the cats' appearances, it is also possible for cats from the same two parents to exhibit significant differences in appearance.

This is due to a combination of dominant and recessive genes, which determine fur color and pattern.

Overall, River and Elsa's unique appearances have sparked curiosity and discussion among internet users. The cats are a prime example of the fascinating genetic variations that can occur within the same litter.