The sound of quills!
Weird, wonderfull and true!
The Lowland-Streaked Tenrec (Hemicentetes semispinosus) is the only mammal with sounding quills. They are one of Madagascar’s fascinating animals that inhabits the islands tropical lowland forest areas. Their black and yellow colours colours make you think of an bumble bee.
These small little creatures that are part of the Tenrec family (Tenrecidae) and in the order Afrosoricida. Besides their exotic appearance, the most wonderous characteristic of these little critters is their sounding quills!
They can use their quills for defence or communication purposes. As a method of defence, some of their quills can even become detached from the body, which reminds one of a porcupine. To understand how the sounding quills work, one must first understand the placement of quills on their body.
The quills are longer and more numerous on the head and nuchal area. However, the ventral region contains few to no quills, but can detach in predation defense.
Just as with other animals that have spines, the Lowland-Streaked Tenrecs has hard keratinous quills, that is in the mid-dorsal region and works as a sounding device. These quills are to be used for communication between mother and young and as a warning signal to predators.
But how do they make these sounds?
Movement of these quills causes the tips to rub together and create a high frequency sound. These quills are in a small area of the mid-dorsal region, in a group of seven to sixteen arranged in three rows. Five quills run laterally on each side and is flanked by five to six quills being light brown in colour. The arrangement and number of quills does not alter during growth and neither does the length. The circumference of the quills, however, does change from juvenile to adult.
Cutaneous muscles underneath the quills that are known as quill vibrator discs. They are around 16.8 mm long and 8.55 mm in width for an adult. These cutaneous muscles are the “tools” that contribute the vibration of the quills and production of ultrasonic sound.
There are two ways that they use the quills:
- Raised when agitated and stridulation:
When agitated or defensive: Quills are raised and in a forward position that causes sound through vibration.
The sound is too high to be heard by the human ear. This is a method well known with crickets, cicadas, and snakes. The streaked tenrec is also the only known mammal that has this ability.
Article by Lizl van Vreden.
Photo Credits: Public Domain- Flickr- Ken Behrens