Don’t blame bats

Usiwalaumu popo. (Scroll down for Swahili translation)

Today is bat appreciation day so let’s take a quick look at why we shouldn’t be blaming bats for coronavirus. Bats do carry a lot of viruses and it is actually really interesting why. This short video gives a brief and easy to understand explanation.

It isn’t really fair to blame bats for zoonosis. That would be like blaming gorillas for malaria, or blaming cows for measles and chimpanzee for HIV. Most of the diseases that have jumped to humans from bats, have actually had another host in between.

Because bats are getting such a bad reputation for carrying diseases, I thought I’d point out some really cool facts about bats.

  • Bats make up 20% of the species of mammals on Earth.
  • All bats are nocturnal.
  • Insect eating bats have evolved a complex method of finding prey and “seeing” at night using sound called echolocation. The sounds they produce are too high for us to hear, but are incredibly loud, so loud in fact that when a bat makes the sound it very briefly closes the hearing mechanism.
  • Bats with big ears for echolocation can collapse their ears by cutting off blood flow when they’re resting. This helps reduce heat loss. They also allow their body temperature to drop to air temperature which reduces energy consumption, but it means they have to warm up before they take to the skies at night.
  • A single insect-eating bat can eat up to 1,000 mosquitos in an hour. Many species are important pollinators. The negative effect to humanity if we were to lose bats far exceeds the risk of viruses.
  • Bats are so efficient at spreading seeds that one organization is building bat houses for reforestation. Bats moved in within 10 days of building bat houses and in their dung carried seeds of over 60 species.
  • Bats have relatively long lifespans- between 30 & 40yrs. Rodents the same size only live a couple years. This may have something to do with their immune systems and be the reason why some of these very dangerous viruses have evolved in bats.
  • Bats don’t seem to rely on bacteria for digestion like other mammals including us. A study of bats in Kenya and Uganda showed us that they do not have the same microbiome in their guts. This may have something to do with high body temperatures achieved when flying. (Read more from the source)
  • A bat holds the record for the fastest horizontal flight of an animal. The fastest birds are swifts and can reach speeds of up to 110kph, but the Brazilian free-tailed bat flies at speeds of up to 160kph. (Peregrine falcons still hold the record for the fastest speed attained in the air when they dive to catch prey reaching over 300kph). (Read more from the source)
  • Bats have super-efficient immune systems and are able to block viruses from entering their cells very quickly. This is partly due to their ability to stop inflammation, again an adaptation due to the high metabolism that they need to fly. (Read more from the source)

Swahili translation:

Kwa vile leo ni siku ya kuthamini popo duniani tuchunguze kidogo sababu za kutokulaumu popo kwa koronavirus. Ni kweli kwamba popo wanabeba virusi vingi na kuna sababu za ajabu. Video hii inamaelezo mafupi na rahisi kuelewa.

Sio sawa kuwalaumu popo kwa magonjwa yaitwayo ‘zoonosis’* (magonjwa yatokanayo na wanyama kwenda kwa binadamu). Hiyo ingefanana na kuwalaumu sokwe mtu (gorilla) kwa malaria, au ng’ombe kwa surua (measles), na sokwe (chimpanzee) kwa kutuambukiza virusi vya ukimwi. Baadhi ya hizi virusi zimeruka kutoka popo kuja kwa binadamu kwa kupitia mnyama mwingine.

Kwa vile popo wanapewa sifa mbaya ya kubeba magonjwa, nilifikiri nionyeshe ukweli poa kuhusu popo.

  • Asilimia 20 ya wanyama aina ya ‘mamalia’ duniani ni popo.
  • Popo wote wanatembea usiku.
  • Popo walao wadudu wamebadilika kuwa na namna changamano ya kuwinda na kuona usiku kwa kutumia sauti ya mwangwi namna inaitwa ‘echolocation’. Sauti wanaoitengeneza ni ya ‘frequency’ juu mno kuliko uwezo wetu kuisikia, lakini ina sauti kubwa hadi wanapotengeneza hiyo sauti wanafunga masikio yao ili isiwafikie.
  • Popo wenye masikio makubwa kwa ajili ya ‘echolocation’ wanaweza kukunja masikio yao kwa kufunga njia ya damu kufika masikioni wanapopumzika. Hii inasaidia kupunguza kupoteza joto mwilini. Pia wanaweza kuruhusu joto ya mwili yao kupungua hadi joto la hali ya hewa, tendo linachopunguza matumizi ya nishati, lakini husababisha ajipashe joto kabla ya kuweza kuruka angani  usiku.
  • Popo wa aina ya kula wadudu anaweza kula hadi mbu elfu mmoja kwa saa mmoja. Spishi nyingi ni wachavushaji wa maua na hasa ya matunda. Hivyo athari kwa binadamu ya kupoteza popo ni kubwa kuliko athari ya virusi.
  • Popo wanaokula matunda wanasambaza mbegu kwa ufanisi mkubwa hadi kuna shirika mmoja linajenga nyumba za popo kwa ajili ya kurudisha misitu. Baada ya siku 10 tu, popo walihamia kwenye nyumba hizo na kuleta mbegu wa miti zaidi ya aina 60 kwenye kinyesi chao.
  • Popo wanaishi muda mrefu- karibia miaka 30 hadi 40. Panya wenye ukubwa sawa na popo wanaishi miaka miwili tu. Hii inaweza kusababishwa na kinga ya miili yao na ndiyo sababu ya virusi hatari kuweza kubadilika kwenye miili ya popo. 
  • Popo huwa hawategemei bakteria kwa kuyeyusha chakula chao kama ‘mamalia’ wengine hata sisi. Utafiti uliofanyika Kenya na Uganda ulionyesha kuwa hawana ‘microbiome’ (aina nyingi za bakteria) kwenye njia ya utumbo. Hii inaweza kusababishwa na joto kali ya miili yao popo wakiruka.
  • Popo ni mwenye rekodi ya kuruka angani kwa mwendo kasi mkubwa kuliko wanyama wengine. Jamii ya ndege wanaoitwa ‘swift’ wanaweza kufikia mwendo kasi wa kilomita 110 kwa saa, lakini spishi ya popo anayeitwa ‘Brazilian free-tailed bat’ ana uwezo wa kufikia mwendo kasi wa kilomita 160 kwa saa. Tai aitwae ‘Peregrine falcon’ baado ana rekodi ya mnyama kufikia mwendo kasi wakati anazama angani wakati wa kuwinda akizidi mwendo kasi wa kilomita 300 kwa saa.
  • Popo wana kinga ya mwili fanisi sana na wanaweza kuzuia virusi kuingia kwenye chembe zao kwa haraka sana. Hii inasababisha wawe na uwezo wa kupunguza uvimbe wa maumivu mwilini. Hii tena inatokana na ‘umetaboli’ (uwezo wao wa kubadilisha chakula kupata nguvu) kubwa wakati wa kuruka angani.

Sources:

Mammals of Africa, Volume IV. Hedgehogs, Shrews & Bats. Edited by Meredith Happold & David Happold.

Coronavirus outbreak raises question: Why are bat viruses so deadly?

https://www.sciencedaily.com/releases/2020/02/200210144854.htm

Bats don’t rely on gut bacteria the way humans do

https://www.sciencedaily.com/releases/2019/11/191112130405.htm

Tropical Reforestation Aided By Bats

https://www.sciencedaily.com/releases/2008/04/080428124235.htm

Brazilian free-tailed bat is the fastest flyer in the animal kingdom

https://www.sciencedaily.com/releases/2016/11/161109113427.htm

3 replies

  1. This is very good information and needs to be used to educate people as amid covid19 out break people may have already had a negative perception towards bats and this could results to endangering their survival. Lets make the proper use of this knowledge to educate and spread awareness to people so as we can save bats across the world

    Like

  2. thanks Ethan – will be great to share this with my Maasai guides and staff in general – keeps all engaged and active, great work – thanks again, see you on the otherside of this – currnelty stuck in lockdown in NZ Chris

    Like

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