Home » blogposts » Lactating creatures with double genitals and the head of a cow. Describing New World ‘whales’ in the sixteenth century.

Lactating creatures with double genitals and the head of a cow. Describing New World ‘whales’ in the sixteenth century.

In his 1554 book on fishes and other aquatic creatures the, at that time, widely renowned French naturalist Guillaume Rondelet described three mysterious species he classified as ‘whales’ from the new world. Although he had very little information on these animals, he was able to report several intriguing and exciting facts about them. All three of them appeared to be mammals, as they gave birth to live young and fed these with milk. One could be trained like a dog. And to top it all off, two have not one, but two full sets of genitals. Which animals were these? Where did Rondelet obtain his information? And what on earth is going on with those double sets of genitals?

Fig. 1 Woodcut portrait of Guillaume Rondelet, from his work Libri de Piscibus Marinis (1554).

Woodcut portrait of Guillaume Rondelet, from his work Libri de Piscibus Marinis (1554). Bibliothèque National de France: Gallica.


Out of character

It was unusual for Rondelet to describe animals he knew very little about. As professor of comparative anatomy at the university of Montpellier, he was convinced that the body parts of animals had been created as perfectly adapted for their specific environment. Consequently, he felt they should be studied in this environment, and he often joined fisherman’s crews to do just that. Following such trips, he took specimens home, kept them in tanks, studied them and experimented on them. Usually, this did not end well for the fish. For example, Rondelet successfully proved, by sealing a tank, that even fish need a supply of fresh air to survive.

Although the fish that helped him prove this gave its life for science, in the end it didn’t matter much, as Rondelet had a habit of eventually dissecting the fish he studied. In short, he considered personal observation part of the foundation of his study of nature, and included in his book only a handful of species he had never seen. An exception was made however, for these species, which he could not successfully identify and of which no depiction could be obtained.  Rondelet provides no further information that that these are species from “the Indies”, by which he means the America’s, without further narrowing down the region, and does not indicate who his source of information was. It is likely he was intrigued by the spectacular descriptions.

Fig. 2 Rondelet_s description of New World ‘whales_ in his Libri de Piscibus Marinis (1554).

Rondelet’s description of New World ‘whales’ in his Libri de Piscibus Marinis (1554). Bibliothèque National de France: Gallica.



He called these three mysterious species, the manatus, tiburus, and maraxus. Only the first is easy to identify. The female manatus, the description reads “has two teats, and produces milk to feed her offspring”. In addition, she is “docile as a dog”, as reported “by those who have seen it”. All and all, we can quite easily conclude that this is a manatee, or sea cow.  These species are cetaceans and mammals and do not often display aggressive behaviour. Most likely this is a West Indian manatee (Trichechus manatus).

Fig. 3 West Indian Manatee. Keith Ramos

West Indian Manatee. Keith Ramos.


This leaves us with the two species that are described as having two sets of genitals. The description states that the tiburus “has a uterus which is divided into two chambers, and several teats” and “gives birth to live young, and feeds them with milk”. The name tiburus may be based on the Spanish tiburón, meaning shark. The remark that the uterus has two chambers could refer to the fact that many shark species are ovo-viviparous. While they produce eggs, these hatch internally, and the offspring are transferred to another part of the reproductive system. This could then be any live-bearing shark species. Since sharks are not mammals, they don’t feed their young with milk, but since they are live-bearing, this assumption is easily made.

Possibly, this is a great white shark (Carcharodon carcharias), tiger shark (Galeocerdo cuvier), or the shortfin mako shark (Isurus oxyrinchus). The fact that the males are described as having double genitalia, “genitale esse aiunt duplex”, may well refer to a shark’s claspers, an extension of the male pelvic fins used in mating. A shark has two claspers, simply because it also has two pelvic fins.


A shark’s claspers. By Jean-Lou Justine (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons.


Fig. 5 Short fin mako shark. Jidanchaomian

Short fin mako shark. Jidanchaomian.


Sources and etymology

That the names would come from Spanish is not altogether surprising. Since the late fifteenth century, Spanish explorers of the new world had encountered aquatic species in the Caribbean. In turn, the name maraxus appears to be based on the Spanish marrajos, a term which can apply to several shark species, but predominantly refers to the shortfin mako shark. However, the marrajos is described in Bartolomé de Las Casas’ Apologetica Historia Sumaria (1527-), where it is said to inhabit shallow waters near the coast. This could indicate that rather than the mako, this could be the great white shark.

Since de Las Casas did not appear in print until 1958, Rondelet would not have been familiar with this text. The earliest work describing aquatic species from the new world, appears to be Gonzalo Fernández de Oviedo’s Sumario de la Natural Historia de las Indias (1526). This discusses turtles, sharks, and the manatee. While he does not indicate this, most likely, this was Rondelet’s source of information.

Fig. 6 Great white shark. George Probst

Great white shark. George Probst.


This still leaves us with one question. Rondelet would have been unfamiliar with the Spanish words tiburón and marrajos. Since the species Spanish explorers encountered in the New World were very different from these they were familiar with, and they consequently lacked words to describe them, they tended to turn to local knowledge and used bastardised Indian names to describe them. According to the lexicographer Fernando Ortiz, tibur´on comes from the Carib language. Possibly ti means ground and bur´on means fish. Similarly towards the end of the sixteenth century, English explorers would adopt the word xoc from the Mayans, which is the root of the word shark.



This being as it may, the double genitals of the tiburus and maraxus should have made Rondelet realise that these were shark species. European shark species, although very different in size to American shark species, also have claspers. In addition, it had been known since antiquity that sharks were live-bearing fishes rather than mammals, as they described as such in Aristotle’s History of Animals. The fact that Rondelet describes these species as producing milk indicates he had not realised they were sharks, but how is this possible? The way in which the description is phrased, “genitale esse aiunt duplex”- they say it has double genitals, could indicate that the author was not convinced this was true. The verb aiunt, meaning ‘they say’, could imply a certain scepticism, which is understandable in relation to this description of a completely unknown animal. Most likely then, Rondelet felt these descriptions were too spectacular to be completely true, and therefore decided not to draw conclusions.




Further reading:

Guillaume Rondelet, Libri de piscibus marinis. Mathieu Bonhomme, Paris, 1554, p. 1-112 (introduction) & 489-490 (manatus, tiburus & maraxus).

Gonzalo Fernández de Oviedo’s Sumario de la Natural Historia de las Indias. Remon de Petras, Toledo, 1526. 

Bartolomé de Las Casas,  Apologetica historia sumaria. Bibliotheca de Autores Españoles 105. Obras Escogidas de Bartolome de las Casas III. Ediciones Atlas, Madrid, 1958.

José I. Castro, Historical Knowledge of Sharks: Ancient Science, Earliest American Encounters, and American Science, Fisheries, and Utilisation. Marine Fisheries Review, 75 (4). 

Ortiz, Fernando. Nuevo catauro de cubanismos. Editorial de Ciencias Sociales, Havana, 1974.



This post also appeared on the Arts in Society Blog.


© Sophia Hendrikx and Fishtories, 2017. Unauthorised use and/or duplication of this material without express and written permission from this site’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Sophia Hendrikx and Fishtories with appropriate and specific direction to the original content.


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