How long do they live? The Olm, also nicknamed the “human fish,” has been estimated to live over 100 years.  Based on longevity research, this blind salamander does not display signs of aging, so they could very well live much longer given the right circumstances. Those circumstances are tough to come by because these little animals are very sensitive to temperature changes [1].

Where are they found? The Olm is an entirely aquatic, cave-dwelling animal found in Europe. They are mainly found north of the Adriatic Sea.

What do they eat? The human fish is classified as an insectivore, but they’ll eat other small animals if it fits in their mouth [2].

What do they look like? Olms only reach about 25 cm in length and they have a pink fleshy appearance, hence how they got the nickname “human fish.” See figures 2 and 3.

p_anguinus1
Figure 1. The Olm, looking much like a graceful water dragon.
proteus_anguinus_postojnska_jama_slovenija
Figure 2. No kidding, their skin really looks like human flesh.

How do they reproduce? Olms do not reach reproductive maturity until around 15 years of age. The male will deposit a spermatophore in front of the female and she’ll pick it up and store it in a sperm storage receptacle called a spermathecae. Following this sperm storage, the female will begin to lay eggs about 3 days later and can continue to lay eggs for over 3 weeks. Interestingly, once the eggs hatch, they immediately develop into adults [2].

How do scientists know how old they are? Mathematical analysis based on breeding and death behaviors that have been being recorded since 1958 [2].

So what are we lacking? There is very little research on this species and only mitochondrial genome data exists on the NCBI website.  How the Olm achieves longevity is only speculation and more thorough studies are needed.

Conservation status: The IUCN Red List indicates that the status of Olms is vulnerable due to human influence through habitat destruction and water pollution. The population may be declining, which sucks because so far this may be the cutest animal I’ve wrote about.

Please contact me if you have any information that you’d like to contribute about these long-lived animals.

  1. Voituron, Yann, et al. “Extreme lifespan of the human fish (Proteus anguinus): a challenge for ageing mechanisms.” Biology Letters (2010): rsbl20100539.
  2. Animal Diversity Web. Proteus anguinus.  http://animaldiversity.org/accounts/Proteus_anguinus/#food_habits. Accessed 9/28/2016