Why do we have hair in such random places? - Nina G. Jablonski

Translator: Sarmoko Sarmoko Reviewer: Maria Nainggolan

We have lots in common with our closest primate relatives.

Kita memiliki banyak kesamaan dengan primata terdekat kita.

But comparatively, humans seem a bit... underdressed.

Jika dibandingkan, manusia tampak sedikit kurang tertutupi.

Instead of thick fur covering our bodies,

Alih-alih ada bulu tebal menutupi seluruh tubuh kita,

many of us mainly have hair on top of our heads—

banyak dari kita punya rambut di atas kepala—

and a few other places.

dan sedikit pada tempat lain.

So, how did we get so naked? And why do we have hair where we do?

Bagaimana kita sebegitu tak tertutupi? Mengapa ada rambut di tempat tertentu?

Human hair and animal fur are made of the same stuff:

Rambut manusia dan bulu hewan terbuat dari bahan yang sama:

filaments of the protein keratin that grow out of organs known as follicles,

filamen dari protein keratin yang tumbuh dari organ bernama folikel,

which go through cycles of growth and shedding.

yang tumbuh dan rontok silih berganti.

Across mammalian species, hairs have been modified for numerous purposes,

Di seluruh mamalia, rambut telah dimodifikasi untuk berbagai tujuan,

ranging from the soft fluff covering rabbits

mulai dari bulu lembut yang menutupi kelinci

to the rigid quills protecting porcupines.

hingga duri kaku yang menutupi landak.

But for many mammals, hair grows in two layers

Tapi bagi banyak mamalia, rambut tumbuh dalam dua lapisan

consisting of a shorter undercoat of ground hairs

yaitu lapisan bawah yang lebih pendek dari bulu-bulu halus

covered by longer guard hairs.

dan ditutupi bulu-bulu pelindung lebih panjang.

Together, they help insulate the animal’s body and protect its skin.

Keduanya bersama-sama menghangatkan tubuh hewan dan melindungi kulitnya.

Human hairs, on the other hand, are kind of a combination of these hair types.

Rambut manusia, di sisi lain, adalah jenis kombinasi dari keduanya.

Unfortunately, hair is rarely found in fossils,

Sayangnya, rambut jarang ditemukan pada fosil

making it hard for researchers to pinpoint when and how

yang menyulitkan peneliti menentukan kapan dan bagaimana

our ancient ancestors lost their coats.

nenek moyang kita kehilangan rambut mereka.

But scientists have developed some working hypotheses.

Tetapi para ilmuwan telah mengajukan beberapa hipotesis.

It seems that, millions of years ago in Africa,

Tampaknya, jutaan tahun yang lalu di Afrika,

early hominins first transitioned out of trees and adopted a more active lifestyle.

hominin purba, pertama pindah dari pohon dan menerapkan gaya hidup lebih aktif.

Keeping cool became increasingly important.

Menjaga tubuh tetap dingin menjadi penting.

Eventually, they developed more sweat glands,

Akhirnya, mereka menghasilkan banyak kelenjar keringat,

which helped them lose heat by evaporating moisture through the skin.

yang menghilangkan panas dengan menguapkan kelembapan lewat kulit.

In fact, humans have 10 times more sweat glands than chimpanzees, for instance.

Ternyata, manusia mempunyai 10 kali kelenjar keringat dari simpanse.

But efficiently losing heat by sweating is harder to do when you’re covered in fur.

Tapi menghilangkan panas akan lebih sulit jika kita tertutup bulu.

Scientists believe that early humans lost much of their coat around this time

Ilmuwan percaya, manusia purba menghilangkan rambut mereka saat itu

to help their sweat evaporate faster.

untuk bisa berkeringat lebih cepat.

However, if losing our hair was so advantageous,

Tetapi, jika menghilangkan rambut sebegitu berguna,

why do we have any left at all?

mengapa kita masih mempunyai rambut?

It seems that there are unique uses for hair in different parts of our bodies.

Tampaknya ada fungsi unik dari rambut pada tempat berbeda di tubuh kita.

When it comes to the tops of our heads,

Rambut di puncak kepala kita

temperature regulation likely played a part again.

berfungsi untuk meregulasi suhu.

Since early humans began venturing into the open,

Sejak manusia purba mulai menjelajah ke tempat terbuka,

their heads would’ve been exposed to the scorching sun.

kepala mereka akan terkena sinar matahari yang terik.

Thicker, longer-growing hair protects our sensitive scalps

Rambut lebih tebal dan lebih panjang melindungi kulit kepala sensitif kita

and keeps our brains from overheating.

dan menjaga otak kita dari kepanasan.

Dark tightly curled hair is most effective at keeping solar radiation off of skin.

Rambut keriting hitam rapat paling efektif untuk menjaga radiasi matahari dari kulit.

Other kinds of head hair evolved as humans moved to different places.

Jenis lain rambut kepala berevolusi karena manusia pindah ke tempat berbeda.

Meanwhile, researchers think eyebrows are especially useful for communication

Sementara itu, para peneliti menganggap alis sangat berguna untuk komunikasi

because they sit atop active facial muscles that convey our feelings.

karena alis ada di atas otot-otot wajah aktif yang menyampaikan perasaan.

Eyelashes have been shown to minimize airflow over our eyeballs,

Bulu mata terbukti meminimalkan aliran udara di atas bola mata,

preventing them from drying out and catching debris.

mencegah mata kering dan menangkap debu.

And maybe facial hair proved helpful in distinguishing identity from a distance,

Mungkin rambut wajah membantu kita membedakan antar orang dari kejauhan,

but we really don’t know.

tetapi kita tak terlalu yakin.

Evidence is stubbly at best.

Adanya bukti tetap yang terbaik.

Why we have hair in other regions is... more pungent.

Mengapa kita punya rambut di daerah lain ... lebih berbau tajam.

Our armpits, nipples, and pubic areas are dotted with apocrine glands.

Ketiak, puting susu, dan area kemaluan dipenuhi dengan kelenjar apokrin.

They produce oily, smelly secretions which the thick, curly hair

Mereka mengeluarkan cairan minyak berbau membuat rambut keriting tebal

that often grows in these spots helps disperse.

tumbuh di sana untuk membantu menyebarkan.

The secretions that waft off these hairy patches may be useful for identification.

Sekret yang keluar dari bercak berbulu ini bisa berguna untuk identifikasi.

For example, several studies have shown that people are able to identify

Misal, beberapa studi menunjukkan orang-orang dapat mengenali

their own armpit odors as well as those of people they’re close with.

bau ketiak dirinya dan orang-orang terdekat.

The final type of notable human hair is the vellus hair that covers our bodies.

Jenis rambut terakhir yaitu rambut vellus yang menutupi tubuh kita.

We don't know if these hairs serve any purpose themselves,

Kita tidak tahu rambut-rambut ini apa gunanya,

but the follicles vellus hair grows from are essential banks of stem cells

tetapi folikel rambut vellus tumbuh dari tempat berkumpulnya sel punca

that repair damaged skin after injury.

yang dapat memperbaiki kulit rusak setelah cedera.

They’re also important sites of nerve endings that convey signals

Di sana juga tempat penting ujung saraf yang menyampaikan sinyal

of gentle touch to the brain.

sentuhan lembut ke otak.

In fact, although it’s much finer,

Meskipun jauh lebih tipis,

humans have roughly the same density of body hair as apes of comparable sizes.

manusia punya kepadatan rambut serupa kera dengan ukuran yang sebanding.

So despite all this talk of human nakedness,

Terlepas dari ceramah ini tentang ketelanjangan manusia,

we're not actually as hairless as we look.

kita tak sepenuhnya tak berambut seperti yang kita lihat.