The Different Types of Urgency Campaigns You Can Create
By Juman Hijab
About 2. Aging is not a foregone conclusion

Table Of Contents
1
Staying young impossibly long
1.1
Naked Mole Rats: An impressively long-lived rodent
1.2
Brandt Bats: longest-lived mammal relative to its size
1.3
Bowhead whales: no reported cases of cancer in this species
1.4
Next article: How does the environment shape longevity?
1.5
References
Brandt Bat - live long

zdenek_macat. Brandt's bat (Myotis brandtii). Shutterstock.

Staying young impossibly long

There are animals that stay young much longer than we would ever expect (1). It is not only that they live longer than their cousins: they stay fertile and maintain a youthful body for most of their lives.


Imagine that we didn't have menopause. Imagine that we didn't have to suffer through our senior years. Imagine that we can live until 100 or even longer maintaining the body of a 30 year old. And then, only in the last 2 years of life that we experience aging. 


That's what naked mole rats, Brandt's bats, and Bowhead whales do.

Naked Mole Rats: An impressively long-lived rodent

The naked mole rat (1, 2, 3, 4) is a species of rodents that live in dry, arid regions of East Africa (for example, Ethiopia, Somalia and Kenya) in extensive underground tunnels. They are the same size of a mouse (30 grams/1 ounce; 10 cm long/2.5 inches). This is the same weight as a single slice of bread. 

Naked mole rat

Aydan Metev. naked mole rat in a terrarium. Shutterstock, ID 1411620992

Naked mole rats are more closely related to porcupines and guinea pigs than they are to rats. This makes sense as both porcupines and guinea pigs are long-lived rodents (23 - 27 years and 12 years) compared to rats (2-4 years) (5). Naked mole rats live 10 x as long as the average mouse, even though they are the same size; they live longer than 30 years.


Naked mole rats have several claims to fame. First, of course, is their longevity (28 - 30 years). Next, they display non-aging. That is, they seem to stay young most of their life. Not only that, the queen of the colony (the only breeding female) remains fertile throughout her life; she - and her 3-4 male consorts - live longer than the rest of the colony rats (2) .


Also, naked mole rats are incredibly resistant to stress. Their cells withstand environmental stresses exceptionally well (4). And living in those underground tunnels, the naked mole rat has to adapt to conditions of hypoxia and cold. Finally, naked mole rats seem immune to cancer. It is very rare for this species of rodents to develop cancer. Compare that to the mouse, where 90% of mice will develop cancer - if they live long enough (5).

Brandt Bats: longest-lived mammal relative to its size

Bats are fascinating creatures. They are the only mammals that fly; they use echolocation for tracking and catching food. They are exceptional pollinators. In fact, some fruits are dependent on bats for pollination, like bananas and and mangoes. Those fruits - and others - would disappear without bats.

The insect-eating Brandt's bat is about 0.25 oz or 1.5 teaspoons in size. Some of those very long-lived Brandt’s myotis bats roost in caves in Siberia. In 2005, a bat was captured for examination; it had a numbered band that had been placed on it in 1964. That bat was at least 41 years old (6). The "old" bat was checked out and released back into its cave.

Brandt Bat - live long

zdenek_macat. Brandt's bat (Myotis brandtii). Shutterstock.

Here's what is fascinating.  Bats (and naked mole rats) are the longest-lived mammals relative to their body size (10). Humans are also relatively long-lived mammals based on their size. As a general rule, the larger an organism is, the longer it lives (12 - 13). The graphic below shows the relationship of age (x-axis/based as log-years) and weight (y-axis/based as log-kg).

Some of this is necessary, given the logistics of size and lifespan. When you achieve a large size, it means that you have had to have the time to get to that size. This means that smaller creatures live shorter lives, as we see with mice and rats. However, there are only 19 species of mammals that are longer-lived than humans when you correct for their body size. Eighteen of those species are bats (10)!

Long lived small mammals

Lifespan versus body mass: Long lived small mammals.

Graph of weight (log) by lifespan (log)

Graph of weight (log) by lifespan (log)

Brandt's bats - like the naked mole rat -   keep their non-aging phenotype for  most of their adult years and are incredibly cancer resistant (7, 8, 9, 10). One curious finding for the diminutive Brandt's bat is a mutation in the Growth Hormone receptor. This may be the clue that allows the bats to remain small, increase longevity, and decrease their incidence of cancer (7). Growth hormone insensitivity (through growth home receptor mutations) has been strongly associated with increased resistance to cancer and diabetes in humans and mice (11).  

Bats have also been found to have multiple genes that are unusually active in DNA repair and maintenance activities (10).

Bowhead whales: no reported cases of cancer in this species

Bowhead whales clearly demonstrate the relationship of body size and longevity.  Bowhead whales can be more the 54,000 kg in weight and live more than 200 years (8). Some whales have reached 100,000 kg in weight.

Interestingly, most of the creatures that enjoy extreme longevity (living hundreds of years) live in the water. Clams, bowhead whales, Greenland sharks, sea urchins easily live 200 or more years:. The only land-based creatures that have lived more than 200 years are the Giant Tortoises. 

Bowhead whale - average lifespan

Blatant World. Bowhead Whales swimming in the Arctic Ocean, Taken Dec 1, 2009. From Flickr.com.

Bowhead whales follow the lead on our long-lived bats and naked mole rats. They stay fertile well into adulthood and maintain resistance to disease as they age as well as a resistance to developing cancer (8, 9, 14, 15). 

Next article: How does the environment shape longevity?

Aging is not a foregone conclusion for all animals. Clearly, there are many animals that defy the odds. And this does not even scratch the surface on animals that live centuries or are thought to be immortal (particularly invertebrates like quahog clams, sea urchins, hydra, and sponges).

How important are environmental factors in longevity?

References

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  2. Schulze-Makuch D. The Naked Mole-Rat: An Unusual Organism with an Unexpected Latent Potential for Increased Intelligence? Life (Basel). 2019 Sep 16;9(3):76. doi: 10.3390/life9030076. PMID: 31527499; PMCID: PMC6789728.
  3. Buffenstein R, Amoroso V, Andziak B, Avdieiev S, Azpurua J, Barker AJ, Bennett NC, Brieño-Enríquez MA, Bronner GN, Coen C, Delaney MA, Dengler-Crish CM, Edrey YH, Faulkes CG, Frankel D, Friedlander G, Gibney PA, Gorbunova V, Hine C, Holmes MM, Jarvis JUM, Kawamura Y, Kutsukake N, Kenyon C, Khaled WT, Kikusui T, Kissil J, Lagestee S, Larson J, Lauer A, Lavrenchenko LA, Lee A, Levitt JB, Lewin GR, Lewis Hardell KN, Lin TD, Mason MJ, McCloskey D, McMahon M, Miura K, Mogi K, Narayan V, O'Connor TP, Okanoya K, O'Riain MJ, Park TJ, Place NJ, Podshivalova K, Pamenter ME, Pyott SJ, Reznick J, Ruby JG, Salmon AB, Santos-Sacchi J, Sarko DK, Seluanov A, Shepard A, Smith M, Storey KB, Tian X, Vice EN, Viltard M, Watarai A, Wywial E, Yamakawa M, Zemlemerova ED, Zions M, Smith ESJ. The naked truth: a comprehensive clarification and classification of current 'myths' in naked mole-rat biology. Biol Rev Camb Philos Soc. 2022 Feb;97(1):115-140. doi: 10.1111/brv.12791. Epub 2021 Sep 3. PMID: 34476892; PMCID: PMC9277573.
  4. Heinze, I., Bens, M., Calzia, E. et al. Species comparison of liver proteomes reveals links to naked mole-rat longevity and human aging. BMC Biol 16, 82 (2018). https://doi.org/10.1186/s12915-018-0547-y
  5. Gorbunova V, Bozzella MJ, Seluanov A. Rodents for comparative aging studies: from mice to beavers. Age (Dordr). 2008 Sep;30(2-3):111-9. doi: 10.1007/s11357-008-9053-4. Epub 2008 Jun 25. PMID: 19424861; PMCID: PMC2527635.
  6. Andrej J. Podlutsky, Alexander M. Khritankov, Nikolai D. Ovodov, Steven N. Austad, A New Field Record for Bat Longevity, The Journals of Gerontology: Series A, Volume 60, Issue 11, November 2005, Pages 1366–1368, https://doi.org/10.1093/gerona/60.11.1366
  7. Seim I, Fang X, Xiong Z, Lobanov AV, Huang Z, Ma S, Feng Y, Turanov AA, Zhu Y, Lenz TL, Gerashchenko MV, Fan D, Hee Yim S, Yao X, Jordan D, Xiong Y, Ma Y, Lyapunov AN, Chen G, Kulakova OI, Sun Y, Lee SG, Bronson RT, Moskalev AA, Sunyaev SR, Zhang G, Krogh A, Wang J, Gladyshev VN. Genome analysis reveals insights into physiology and longevity of the Brandt's bat Myotis brandtii. Nat Commun. 2013;4:2212. doi: 10.1038/ncomms3212. PMID: 23962925; PMCID: PMC3753542.
  8. Albuquerque TAF, Drummond do Val L, Doherty A, de Magalhães JP. From humans to hydra: patterns of cancer across the tree of life. Biol Rev Camb Philos Soc. 2018 Aug;93(3):1715-1734. doi: 10.1111/brv.12415. Epub 2018 Apr 16. PMID: 29663630; PMCID: PMC6055669.
  9. Jiang JJ, Kong QP. Comparative analysis of long noncoding RNAs in long-lived mammals provides insights into natural cancer-resistance. RNA Biol. 2020 Nov;17(11):1657-1665. doi: 10.1080/15476286.2020.1792116. Epub 2020 Jul 17. PMID: 32635806; PMCID: PMC7567513.
  10. Foley NM, Hughes GM, Huang Z, Clarke M, Jebb D, Whelan CV, Petit EJ, Touzalin F, Farcy O, Jones G, Ransome RD, Kacprzyk J, O'Connell MJ, Kerth G, Rebelo H, Rodrigues L, Puechmaille SJ, Teeling EC. Growing old, yet staying young: The role of telomeres in bats' exceptional longevity. Sci Adv. 2018 Feb 7;4(2):eaao0926. doi: 10.1126/sciadv.aao0926. PMID: 29441358; PMCID: PMC5810611.
  11. Guevara-Aguirre J, Balasubramanian P, Guevara-Aguirre M, Wei M, Madia F, Cheng CW, Hwang D, Martin-Montalvo A, Saavedra J, Ingles S, de Cabo R, Cohen P, Longo VD. Growth hormone receptor deficiency is associated with a major reduction in pro-aging signaling, cancer, and diabetes in humans. Sci Transl Med. 2011 Feb 16;3(70):70ra13. doi: 10.1126/scitranslmed.3001845. PMID: 21325617; PMCID: PMC3357623.
  12. Speakman JR. Body size, energy metabolism and lifespan. J Exp Biol. 2005 May;208(Pt 9):1717-30. doi: 10.1242/jeb.01556. PMID: 15855403.
  13. Hulbert AJ, Pamplona R, Buffenstein R, Buttemer WA. Life and death: metabolic rate, membrane composition, and life span of animals. Physiol Rev. 2007 Oct;87(4):1175-213. doi: 10.1152/physrev.00047.2006. PMID: 17928583.
  14. Keane M, Semeiks J, Webb AE, Li YI, Quesada V, Craig T, Madsen LB, van Dam S, Brawand D, Marques PI, Michalak P, Kang L, Bhak J, Yim HS, Grishin NV, Nielsen NH, Heide-Jørgensen MP, Oziolor EM, Matson CW, Church GM, Stuart GW, Patton JC, George JC, Suydam R, Larsen K, López-Otín C, O'Connell MJ, Bickham JW, Thomsen B, de Magalhães JP. Insights into the evolution of longevity from the bowhead whale genome. Cell Rep. 2015 Jan 6;10(1):112-22. doi: 10.1016/j.celrep.2014.12.008. PMID: 25565328; PMCID: PMC4536333.
  15.  George JC, Bada J, Zeh J, Scott L, Brown SE, O'Hara T, and Suydam R. Age and growth estimates of bowhead whales (Balaena mysticetus) via aspartic acid racemization. Can J Zool 1999 77: 571 - 580.

Done?

Mark lesson complete
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