Yashpal Rathore / Indian crested porcupine (Hystrix indica) foraging at night. Nilgiri Biosphere Reserve, India. Camera trap image.

Yashpal Rathore / Indian crested porcupine (Hystrix indica) foraging at night. Nilgiri Biosphere Reserve, India. Camera trap image.

Ernie Janes / Indian crested porcupine (Hystrix indica) close up of quill pattern, captive.

Ernie Janes / Indian crested porcupine (Hystrix indica) close up of quill pattern, captive.

Paul Williams / North American porcupine (Erethizon dorsatum), in defensive posture with erect quills. Vermont, USA. (Habituated rescued individual returned to the wild)

Linda Pitkin / Short-quill sea pen (Virgularia gustaviana) Rinca, Komodo National Park, Indonesia.

Albert Lleal / Porcupine (Hystricidae) quill cross-section, magnified at 100x

Tony Heald / Yacare caiman (Caiman yacare) with porcupine quills stuck all over face, Pantanal, Brazil

David Noton / Quill Creek with the Auriol Range, St Elias Mountains, Kluane National Park, Yukon Territories, Canada, September 2013.

David Noton / Quill Creek with the Auriol Range, St Elias Mountains, Kluane National Park, Yukon Territories, Canada, September 2013.

Juan Carlos Munoz / Close up of Porcupine quills (Hystricidae) captive.

Robin Chittenden / Child drawning with quill and ink made from berries, Norfolk, England, UK, December

Michael Quinton / Common Porcupine (Erethizon dorsatum) quills, Alaska

Heidi & Hans-Juergen Koch / Brown-breasted Hedgehog (Erinaceus europaeus), Lottstetten, Baden-Wuerttemberg, Germany

Heidi & Hans-Juergen Koch / Crested Porcupine (Hystrix cristata) in defensive posture, Krefeld, North Rhine-Westphalia, Germany

Heidi & Hans-Juergen Koch / Crested Porcupine (Hystrix cristata) in defensive posture, Krefeld, North Rhine-Westphalia, Germany

Michael Quinton / Common Porcupine (Erethizon dorsatum) quills, Slana, Alaska

TJ Rich / Bengal Tiger {Panthera tigris tigris} looking alert, note Porcupine quill stuck in neck, Ranthambhore NP, Rajasthan, India

Michael & Patricia Fogden / Bicolored Quill-nosed Snake (Xenocalamus bicolor) portrait, close up, southern Africa

Michael & Patricia Fogden / Bicolored Quill-nosed Snake (Xenocalamus bicolor) coiled, southern Africa

Michael & Patricia Fogden / Bicolored Quill-nosed Snake (Xenocalamus bicolor) portrait, Kalahari, Namibia

Pete Oxford / Lion {Panthera leo} male with porcupine quill in muzzle, Okavango Delta, Botswana

Heidi & Hans-Juergen Koch / Crested Porcupine (Hystrix cristata) quills, native to Africa

Heidi & Hans-Juergen Koch / Brown-breasted Hedgehog (Erinaceus europaeus) in defensive posture, Lottstetten, Baden-Wurttemberg, Germany

Heidi & Hans-Juergen Koch / Brown-breasted Hedgehog (Erinaceus europaeus) quills, Lottstetten, Baden-Wuerttemberg, Germany

Heidi & Hans-Juergen Koch / Brown-breasted Hedgehog (Erinaceus europaeus) quills, Lottstetten, Baden-Wuerttemberg, Germany

Heidi & Hans-Juergen Koch / Brown-breasted Hedgehog (Erinaceus europaeus), Lottstetten, Baden-Wuerttemberg, Germany

Heidi & Hans-Juergen Koch / Brown-breasted Hedgehog (Erinaceus europaeus), Baden-Wurttemberg, Germany

Heidi & Hans-Juergen Koch / Crested Porcupine (Hystrix cristata) quills, native to Africa, Krefeld, North Rhine-Westphalia, Germany

Paul D Stewart / Early Lithographic print by Honegger drawn by Fuchs, from Dr. Shinz, 'Naturgeschichte und Abbilldungen des Menschen der verschiedenen' 1827/1840, with hand colouring. A trio of Papua New Guinea men wi...

Roland Seitre / Crested porcupine (Hystrix cristata) leucistic, climbing over rocks, Refuge Decan, Republic of Djibouti.

Roland Seitre / Two Crested porcupines (Hystrix cristata) one leucistic, portrait, Refuge Decan, Republic of Djibouti.

Roland Seitre / Crested porcupine (Hystrix cristata) quills detail, Refuge Decan, Republic of Djibouti.

Etienne Littlefair / Short-beaked echidna (Tachyglossus aculeatus) exploring the base of a deep sandstone gorge at night, Adelaide River Hills, Northern Territory, Australia.

Etienne Littlefair / Short-beaked echidna (Tachyglossus aculeatus) resting on rock during the day, Adelaide River Hills, Northern Territory, Australia.

Robin Chittenden / European hedgehog (Erinaceus europaeus) juvenile, foraging in leaf litter, Norfolk, UK. October.

Robin Chittenden / European hedgehog (Erinaceus europaeus) juvenile, foraging in leaf litter, Norfolk, UK. November.

Roland Seitre / Pink quill (Tillandsia cyanea) in flower, Waimanalo Forest Reserve, Oahu, Hawaii.

Joel Sartore / Photo Ark / Cape porcupine (Hystrix africaeaustralis) portrait, John Ball Zoo. Captive, occurs in Southern Africa.

Joel Sartore / Photo Ark / Cape porcupine (Hystrix africaeaustralis) head portrait, John Ball Zoo. Captive, occurs in Southern Africa.

Joel Sartore / Photo Ark / Cape porcupine (Hystrix africaeaustralis) portrait, John Ball Zoo. Captive, occurs in Southern Africa.

Roland Seitre / North American porcupine (Erethizon dorsatum) feeding, captive in zoo. Occurs in North America.

Roland Seitre / North American porcupine (Erethizon dorsatum) captive in zoo.Occurs in North America.

Roland Seitre / African brush-tailed porcupine (Atherurus africanus) portrait, Africa. Captive.

Roland Seitre / Philippine porcupine (Hystrix pumila) portrait, Philippines. Captive.

Roland Seitre / Crested porcupine (Hystrix cristata) female with infant, portrait, Morocco. Captive.

Joel Sartore / Photo Ark / Mexican hairy dwarf porcupine (Coendou mexicanus) head portrait, Philadelphia Zoo. Captive.

Joel Sartore / Photo Ark / Orange-spined hairy dwarf porcupine (Coendou spinosus) portrait, Membeca Lagos Farm, Brazil. Captive.

Joel Sartore / Photo Ark / Asiatic brush-tailed porcupine (Atherurus macrourus) portrait, Zoo Taiping. Captive.

Neil Aldridge / Cape porcupine (Hystrix africaeaustralis) expanding its quills in a response to danger while feeding, Hoedspruit, South Africa.