How Tardigrades Work

Waterbear Coda
Tardigrades float around with some algae.
Tardigrades float around with some algae.
Roland Birke/Photographer's Choice/Getty Images

Ah, science. Science is fun, science is fascinating, but science also plays hardball. It's not a profession for the faint of heart or for those who get sentimentally attached to a research result. Boothby and his team knew very well that their tardigrade study had surprising findings, and they also knew that all those foreign genes might be the result of contamination (i.e., some bits of fungi and bacteria might've managed to get mixed in with the tardigrade sample by accident).

They knew that because contamination happens all the time. It's all too easy for bits of floating bacteria and fungi to get mixed in with a sample. So the team double and triple checked their results with increasingly sophisticated technology. It seems you can't be too careful when it comes to sequencing genomes.

The digital ink was barely dry on all the excited press coverage of the Boothby team's findings before a careful review of the evidence by other scientists found that there was, in fact, a ton of contamination involved. After reanalyzing the sequencing, it appeared that instead of a whopping 17.5 percent foreign gene count, the tardigrade species in question had only about 0.4 percent of the stuff. And that, it turns out, is a pretty standard amount [source: Richards and Monier]. In other words, there is evidence of horizontal gene transfer in tardigrades, as there is in all organisms (including us), just not very much of it — which is, as it turns out, the usual amount.

So it turns out that tardigrades aren't a perfect metaphor for the durability of multicultural societies, but they're still cool nonetheless. They've been around for 500 million years, so they can surely teach us a thing or two, like how to survive in outer space, how to repair our DNA and how to get our own phylum.

Best of all, you can keep them as pets! All you need is a little container, some moss, a microscope and a really small leash (you'll have to special-order it). The only downside is that you can't really give them names — or you can, but since they're all nearly identical, it'll be tough telling Charles from Charlene and Charles Jr.

Author's Note: How Tardigrades Works

Much of the scientific literature on tardigrades makes mention of how "cute" they are. I think this must be a matter of context. If you spend a lot of time staring through a microscope at weird-looking creatures, your standards for cuteness must necessarily be lowered. Personally, I find tardigrades grotesque. I mean, I greatly respect their invincibility, but they look like a cross between a mole and an overstuffed pool raft. But beauty is as beauty does.

Related Articles

More Great Links


  • American Museum of Natural History. "Tardigrades as Environmental Bio-Indicators." (Dec. 22, 2016)
  • Boothby, Thomas C. et al. "Evidence for extensive horizontal gene transfer from the draft genome of a tardigrade." Proceedings of the National Academy of Sciences of the U.S.A. Vol. 112, No. 52. Pp. 15976-15981. Dec. 29, 2015. (Jan. 6, 2016)
  • Brennand, Emma. "Tardigrades: Water bears in space." BBC. May 17, 2011. (Dec. 22, 2016)
  • Dvorsky, George. "Scientists Finally Figured Out Why Tardigrades Are So Indestructible." Gizmodo. Sept. 20, 2016. (Dec. 22, 2016)
  • Fox-Skelly, Jasmin. "Tardigrades return from the dead." BBC. March 13, 2015. (Dec. 22, 2016)
  • Gray, Michael W. "Mitochondrial Evolution." Cold Spring Harbor Perspectives in Biology. Vol. 4, No. 9. September 2012. (Dec. 21, 2016)
  • Herkewitz, William. "Secrets of the Water Bear, the Only Animal That Can Survive in Space." Popular Mechanics. Aug. 7, 2014. (Jan. 13, 2016)
  • Keeling, Patrick J. and Jeffrey D. Palmer. "Horizontal gene transfer in eukaryotic evolution." Nature Reviews Genetic. Vol. 9. Pp. 605-618. August 2008. (Dec. 22, 2016)
  • Lindahl, Karen and Susie Balser. "Tardigrade Facts." Illinois Wesleyan University Species Distribution Project. October 1999. (Jan. 13, 2016)
  • Miller, William R. "Tardigrades." American Scientist. September-October 2011. Vol. 99, No. 5. Pg. 384. (Dec. 23, 2016)
  • Minard, Anne. "Gamma-Ray Burst Caused Mass Extinction?" National Geographic. April 3, 2009. (Dec. 23, 2016)
  • Ochman, Howard et al. "Lateral gene transfer and the nature of bacterial innovation." Nature. Vol. 405. May 18, 2000. (Dec. 22, 2016)
  • O'Malley, Maureen A. "Endosymbiosis and its implications for evolutionary theory." Proceedings of the National Academy of Sciences of the U.S.A. Aug. 18, 2015. Vol. 112, No. 33. Pp. 10270-10277. (Dec. 21, 2017)
  • Richards, Thomas A. and Adam Monier. "A tale of two tardigrades." Proceedings of the National Academy of Sciences of the USA. Vol. 113, No. 18. Pp. 4892-4894. (Dec. 22, 2016)
  • Stromberg, Joseph. "How Does the Tiny Waterbear Survive in Outer Space?" Smithsonian. Sept. 11, 2012. (Dec. 22, 2016)
  • Understanding Evolution. "From prokaryotes to eukaryotes." UC Berkeley. (Dec. 21, 2016)
  • WikiHow. "How to Find and Care for a Pet Tardigrade (Water Bear)." (Dec. 22, 2016)
  • Yong, Ed. "Inside the Bizarre Genome of the World's Toughest Animal." The Atlantic. Nov. 23, 2015. (Dec. 21, 2016)

More to Explore