Seismic communication
Vibrations can provide cues to conspecifics about specific behaviours being performed, predator warning and avoidance, herd or group maintenance, and courtship.
It was eventually realised they generate temporally patterned vibrational signals for long-distance communication with neighbouring mole-rats.
It is used primarily by fossorial or semi-fossorial rodents, but has also been recorded for spotted skunks (Spilogale putorius), deer (e.g. white-tailed deer Odocoileus virginianus), marsupials (e.g. tammar wallabies Macropus eugenii), rabbits (e.g. European rabbits Oryctolagus cuniculus) and elephant shrews (Macroscelididae).
[2] Banner-tailed kangaroo rats (Dipodomys spectabilis) footdrum in the presence of snakes as a form of individual defense and parental care.
[3][4] Several studies have indicated intentional use of ground vibrations as a means of intra-specific communication during courtship among the Cape mole-rat (Georychus capensis).
[7] Other insects use vibrational communication to search for and attract mates, like North American treehoppers, Enchenopa binotata.
[8][9][10] The banner-tailed kangaroo rat, (Dipodomys spectabilis), produces several complex footdrumming patterns in a number of different contexts, one of which is when it encounters a snake.
Wood turtles (Clemmys insculpta),[14] European herring gulls (Larus argentatus),[15] and humans[16] have learnt to vibrate the ground causing earthworms to rise to the surface where they can be easily caught.
[17] Portia fimbriata jumping spiders lure female Euryattus species by mimicking male courtship vibrations.
[18] The wandering spider (Cupiennius salei) can discriminate vibrations created by rain, wind, prey, and potential mates.
This process involves rocking of the entire body with the subsequent vibrations being transferred through the legs to the substrate on which the insect is walking or standing.
Elephants produce low-frequency vocalizations at high amplitudes such that they couple with the ground and travel along the surface of the earth.
[6] Direct percussion can produce a much stronger signal than airborne vocalizations that couple with the ground, as shown in the Cape mole rat and the Asian elephant.
It has been suggested that other large mammals such as the lion and rhinoceros may produce acoustically coupled vibrational cues similar to elephants.
[28] The star-nosed mole (Condylura cristata), has evolved an elaborate nose structure which may detect seismic waves.
[6][31] In areas with little to no human-generated seismic noise, frequencies around 20 Hz are relatively noise-free, other than vibrations associated with thunder or earth tremors, making it a reasonably quiet communication channel.
[24] Vibrational signals are probably not very costly to produce for small animals, whereas the generation of air-borne sound is limited by body size.
One of the earliest reports of vertebrate signaling using vibrational communication is the bimodal system of sexual advertisement of the white-lipped frog (Leptodactylus albilabris).
Males on the ground sing airborne advertisement songs that target receptive females, but instead of supporting themselves on their front limbs as other frogs often do, they partially bury themselves in soft soil.
As they inflate their vocal sacs to produce the airborne call, the gular pouch impacts the soil as a ‘thump’ that sets up Rayleigh waves which propagate 3–6 m through the substrate.
The Namib Desert golden mole (Eremitalpa granti namibensis) is a blind mammal whose eyelids fuse early in development.
[12] In the late 1990s, Caitlin O'Connell-Rodwell first argued that elephants communicate over long distances using low-pitched rumbles that are barely audible to humans.
This research is helping our understanding of behaviours such as how elephants can find distant potential mates and how social groups are able to coordinate their movements over extensive ranges.
[49] Seismic energy transmits most efficiently between 10–40 Hz, i.e. in the same range as the fundamental frequency and 2nd harmonic of an elephant rumble.
The cushion pads of the feet contain cartilaginous nodes and have similarities to the acoustic fat (melon) found in marine mammals like toothed whales and sirenians.
When detecting the vibrational cues of an alarm call signaling danger from predators, elephants enter a defensive posture and family groups will congregate.
After the 2004 Boxing Day tsunami in Asia, there were reports that trained elephants in Thailand had become agitated and fled to higher ground before the devastating wave struck, thus saving their own lives and those of the tourists riding on their backs.
Once finding a suitable growing stem for the other C. pinguis larvae, it begins to send short vibrations to the old site.
[56] Gryllotalpa major (prairie mole crickets), however, use underground vibrational cues as one part of their mating call.
[57] Psammodes striatus repeatedly taps its abdomen on the ground, sending vibrational cues to communicate with other beetles.
