While lately perusing online some 19th-Century back numbers of the Antananarivo Annual and Madagascar Magazine (a yearly periodical that has proved very fruitful in providing me with fascinating but hitherto-obscure, cryptozoologically-unreported material concerning Malagasy mystery beasts of many kinds), I chanced upon a truly bizarre report regarding ants and snakes that as far as I am aware has not been previously blogged about online.
Appearing in this periodical's Christmas 1875 issue, it consisted of the following account, from an article written by Madagascan traveller/clergyman Rev. H.W. Grainge and entitled 'Journal of a visit to Mojanga and the north-west coast':
We also noticed about this part a large number of earthen mounds, varying from one to two and a half feet in height; these were the nest of a large ant credited by the men with uncommon sagacity. We were told that they make regular snake traps in the lower part of these nests; easy enough for the snake to enter, but impossible for it to get out of. When one is caught the ants are said to treat it with great care, bringing it an abundant and regular supply of food, until it becomes fat enough for their purpose; and then, according to native belief, it is killed and eaten by them.
(Mojanga is nowadays known as Mahajanga, or Majunga in French – Madagascar is a former French colony; these names are applied to a city and administrative district on Madagascar's northwest coast.)
Rev. Grainge's macabre little vignette attracted the attention of a reader named R. Toy, who duly quoted it exactly a year later, in the Christmas 1876 issue of the Antananarivo Annual and Madagascar Magazine, and then appended his own equally interesting firsthand experiences concerning this very curious affair:
It would be interesting if some missionary living in the country would test the reality of this reputed fact by digging open a few of these nests. There is no doubt but that the belief is most universal among the natives. I have been assured most confidently over and over again that it is a fact that snakes are kept and fattened by the ants as above described; and knowing the sagacity of ants, and the care they take in feeding the aphides for the sake of their honey, one would not hastily set aside the statement, so generally accepted by the natives, as devoid of truth.
Needless to say, just because a belief is widely accepted does not necessarily make it true, as the very widely accepted yet wholly fallacious belief in hoop snakes, for instance, readily demonstrates. Equally, however, as noted by Toy, the farming and milking of aphids by ants for their sweet secretions is well documented scientifically. So too is their rearing within their nests of the caterpillars of the large blue Phengaris arion, a Eurasian species of lycaenid butterfly.
(Although in this latter instance, the ants are the unsuspecting victims of a lepidopteran version of brood parasitism, with the large blue's caterpillars actually acting as predators after having tricked the ants via morphological and pheromonal mimicry tactics into carrying them inside their nests, then feeding them there; the caterpillars also take the opportunity to prey upon the ants' own pupae).
Even so, it is an immense step up, behaviourally speaking, from ants feeding 'cuckoo' caterpillars that they have been tricked into bringing inside their nests to ants purposefully trapping snakes inside their nests, then fattening them up, before killing them specifically to devour them. Such a highly advanced strategy has no readily apparent, direct parallels elsewhere in the ant, or indeed in the entire insect, world – or does it? Read on.
In August 2019, a trio of Japanese researchers who included Teppei Jono published a fascinating Royal Society Open Science paper (click here to access it) revealing two very different but closely interacting relationships between a species of Madagascan myrmicine ant Aphaenogaster swammerdami and two species of snake, all of which was hitherto unsuspected by science and unequivocally novel. The snakes are a large ant-eating blindsnake called Mocquard's worm snake Madatyphlops decorsei, and an even larger ophiophagous (snake-eating) lampropheid called the Malagasy cat-eyed snake Madagascarophis colubrinus (also known locally as the ant mother – see later).
Native to much of the world (sub-Saharan Africa, much of South America, and Antarctica being the only major exceptions), there are approximately 200 species of Aphaenogaster ant, which belong to the taxonomic subfamily Myrmicinae, and produce just a single caste of worker. They are famous for their large funnel-shaped nests (more about which later), earning them the common name of funnel ants. In Madagascar, a major predator of these ants is Mocquard's worm snake Madatyphlops decorsei, endemic to this mini-island continent, and formally described by French herpetologist Dr François Mocquard in 1901, who named it in honour of Gaston-Jules Decorse, a French army physician.
Mocquard assigned this newly-revealed species to the nominate blindsnake genus Typhlops, where it remained until 2014 when a new genus, Madatyphlops, was specifically created for the blindsnakes of Madagascar and the Comoros (14 species are currently recognised), and to which it was duly transferred (and of which it is the largest species). Dark shiny grey-brown dorsally, paler ventrally, this species spends its life underground, explaining why it only has vestigial eyes.
As for the Malagasy cat-eyed snake or ant mother Madagascarophis colubrinus, this species is an active predator of Mocquard's worm snake and is a member of the taxonomic family Lampropheidae. The latter was long considered to be merely a subfamily of Colubridae, but was elevated to the level of a family in its own right in 2010 when a molecular-based study revealed that in reality its member species were more closely allied to the elapids than to the colubrids. Very variable in colour and markings, M. colubrinus is one of five species housed within its genus, endemic to Madagascar, and all are mildly venomous, but they are capable of constriction too if their venom proves insufficient to subdue their prey. This consists of other small reptiles, including snakes as already noted, plus rodents. They have large eyes with vertical, superficially cat-like pupils, hence their common name.
According to a publicity release (click here to access it) issued on Scimex when the Japanese team's August 2019 paper was published:
A Madagascan ant species can tell whether marauding snakes are friend or foe. When ant-eating blind snakes approach an ant nest, the worker ants run back to evacuate their young, leaving a few behind to mount a biting attack on the intruder. But they also have a second line of defence. The ants allow one of the few known predators of the blindsnake - a snake-eating snake - into their nest, in what the authors say is a symbiotic relationship where the ants get protection and the snake gets a cosy place to hide. Instead of biting the snake-eating snake when it approaches, the ants touch them with their antenna - a well-known form of communication between ants.
In the past, differences in reactions by ants to other species had only occurred relative to different insect predators or aggressors. Consequently, as noted by University of York researcher Dr Eleanor Drinkwater in a Naked Scientists website interview on 20 August 2019 concerning this study by Jono et al., the latter might be the first study to show that ants react differently to different vertebrate predators too. When the researchers conducted experiments to determine the ants' reactions to these snakes, presenting to various nests of this ant species a specimen of each of the two snakes plus one of a third, control snake species, the ants ignored the ant mother snake, but attacked the blindsnake and also the control snake. However, the only snake that sent the ants fleeing back inside their nest to evacuate it was the blindsnake.
Reading this remarkable discovery has made me wonder whether it may have influenced the native Madagascan belief in ants trapping, fattening up, and then killing snakes. After all, the reason why the local tribespeople refer to M. colubrinus as the ant mother is that they are well aware of its frequent presence around the nests of this particular species of ant, and that it preys upon the blindsnakes preying upon the ants, thereby indirectly protecting the ants.
Also, the nests of some Aphaenogaster ants are both funnel-shaped and deep, conceivably giving a false impression that they have been specially created as inescapable traps for snaring creatures. (Having said that, it is possible that in certain Australian Aphaenogaster species, their nests' funnel-shaped entrances do act as traps for surface foraging arthropods.)
Could it be, therefore, that the Madagascan locals knew of the ants' different specific reactions to these two snakes too, long before the researchers scientifically revealed them recently, but that down through many generations of verbal retellings the true nature of these reactions and also of their nests had become distorted and elaborated upon, eventually yielding an imaginative but wholly incorrect scenario whereby the ants do not merely attack the blindsnakes but actually trap, feed, and then feed upon them?
After all, it wouldn't be the first time that garbled, orally-transmitted recollections of elusive animals and unusual animal behaviour by non-scientific observers has resulted in the evolution of memorable yet entirely erroneous folk beliefs.
Finally: after discovering the two above-quoted reports in two successive early volumes of the Antananarivo Annual and Madagascar Magazine, I painstakingly checked through every succeeding volume of it, and also widely elsewhere online, but I have been unable to uncover any additional reports on this most curious subject.
Consequently, it presently remains a herpetological enigma – unless anyone reading this ShukerNature blog article of mine has further information? If so, I'd love to hear from you!