Many mammals rely on vocalizations to communicate, so it may come as a surprise that some lack vocal cords entirely. If you’re short on time, here’s a quick answer: Giraffes, anteaters, golden moles, and echidnas are examples of mammals born without vocal cords that have adapted other means of communication.
In this comprehensive guide, we will explore several mammal species that lack vocal cords and detail how they communicate without them. We will look at their evolutionary adaptations, methods of sound production, and unique behaviors that facilitate bonding, mating, warning calls, and more.
Mammals Born Without Vocal Cords
Giraffes
Giraffes are born without vocal cords, leaving them literally speechless. So how do these tall drink of waters communicate? Research shows giraffes utilize body language and non-vocal sounds to interact. For example, a gentle humming during feeding signifies contentment.
Dominant males will participate in a practice called “necking” where they swing their long necks and heads at each other to establish hierarchy. Their silence may be why giraffes rub noses in greeting to exchange scents from unique glands; a non-verbal “hello.”
Anteaters
Anteaters like giant anteaters, tamanduas, and pangolins also lack vocal cords. Instead, they emit a variety of snorting, sniffing, and hissing sounds to communicate danger, location, breeding readiness, and protection of resources like a termite mound!
Anteaters have also been observed using body language like claw positioning, tail wagging, and back arching to state feelings from aggression to courtship.
Golden Moles
Golden moles possess no external eyes or ears, limiting interaction with the visible world. As strictly underground dwellers, they maneuver using a star-nosed nose and whiskers that detect subtle vibrations and gradients from tunnels to threats.
While lacking functional vocal cords, they can issue low-frequency squeaks to warn of predators and chirps during mating encounters. Due to their environment and physical adaptations, golden moles primarily use non-audible cues like seismic tremors to interact.
Echidnas
Echidnas or spiny anteaters communicate through tactile, olfactory, and auditory means since they lack exterior ears and a vocal box. They emit low guttural growls, almost silent purring, and audible hisses when defending themselves or showing courtship interest through protruding spines.
Their beaks allow them to probe leaf litter and dirt for insects and worms detected by specialized electroreceptors on their snout and tongue. While not overly vocal besides mother and babies, echidnas use a broad range of non-verbal behaviors to interact.
Evolutionary Adaptations for Sound Production
Snorts, Grunts, Hisses, and Humming
Many mammals like elephants, rhinos, and tapirs lack vocal cords but have evolved other ways to produce sounds. Elephants use their trunks to produce powerful trumpeting calls that can be heard over long distances. They snort, grunt, and make rumbling sounds to communicate with each other.
Rhinos also snort loudly as warnings or greetings. Tapirs hiss, chirp, whistle, and even hum to interact with each other! These sounds may not have the complexity of those produced by vocal cords, but are still an effective means of communication.
Foot Stomping
Some mammals like gorillas and okapis stomp their feet on the ground to produce booming sounds that convey information. Gorillas vigorously beat their chests as intimidating displays and slam their cupped hands on the ground to grab attention or show dominance.
The elusive okapi similarly slams its striped forelegs on the ground to signal alarm or warn others to back off. Ground stomping creates vibrations that can travel long distances to mark territory or notify others of danger. It’s an ingenious use of body parts to compensate for lack of vocalizations.
Rapid Exhalation Through Nose
Giraffes have no vocal cords but make various sounds by forcefully exhaling through their long nostrils. Courting males blow air out in snorts and wheezes to attract females. Newborn calves use high-pitched sneeze-like sounds to seek their mothers if separated.
Giraffes also grunt, moan, and make flute-like sounds. Their large nasal passages allow rapid expulsion of air to produce low-frequency infrasonic calls below human hearing range. These adaptations enable giraffes to communicate effectively despite anatomical constraints.
Stomach Rumbling
Some vocal mammals like koalas and kangaroos lack vocal cords but can convey information through stomach rumbles. Male koalas produce loud gurgling sounds during mating season by churning the air in their intestines. The low-pitched bellows help attract females and warn competing males to keep away.
Mother kangaroos also rumble in their stomachs to guide lost joeys back to the safety of the pouch. Vibrations from these intestinal noises travel through tissues to serve as beacons. Using guttural sounds shows ingenious adaptation to anatomical limitations on vocalization.
alternate Communication Methods
Body Language and Posture
Since mammals without vocal cords lack the ability to vocalize, they rely heavily on body language and posture to convey information. Subtle changes in facial expressions, tail positioning, ear orientation, and body stance can speak volumes.
For example, dogs communicate happiness by wagging their tails, while cats communicate aggression by flattening their ears. Elephants express a range of emotions through slight posture changes – ears forward means attentiveness, while ears flared out means aggression.
Understanding the nuances of nonverbal communication is key to understanding mammals without voices.
Scent Marking
Scent is an incredibly important communication method for non-vocal mammals. Species like otters and hyenas use scent glands to leave smelly messages on trees, rocks, or the ground. These chemical signals convey all kinds of information – territory boundaries, reproductive status, social hierarchy, and identity.
Scent marking is advantageous because smells persist in the environment for a long time, allowing individuals to leave ‘status updates’ for others to find later. The complexity of messages that can be encoded in scent is quite remarkable.
Touch and Vibration Sensitivity
For species that live underground or in the water, touch and vibration take precedence over visual and auditory signals. Naked mole rats communicate by bumping their bodies against each other in certain ways.
Aquatic mammals like seals, walruses, and manatees rely on touch through flipper stroking, nuzzling, and gentle body contact. Vibrations are used extensively by moles, who stomp their feet to send seismic signals.
Sensitivity to touch and vibrations enables communication to occur even in low-light conditions where vision is limited. For non-vocal mammals, these alternate sensory modes allow sophisticated social structures to develop through the tactile channel.
Conclusion
While most mammals vocalize with their larynx and vocal cords, some species lack these anatomical features entirely. Giraffes, anteaters, golden moles, echidnas, and more, have evolved alternate methods of communication.
Through specialized adaptations like snorts, foot stomping, ultrasonic humming, and keen sensitivity to touch, these mammals bond with their young, court mates, establish hierarchy, mark territory, and warn others of danger despite their lack of vocal cords.
Next time you hear a giraffe’s snort or glimpse an anteater’s fluttering tongue, remember the incredible diversity of adaptations mammals have evolved to facilitate communication and survival.