Seawater ingestion by the Mauritius flying fox

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Afr J Ecol. 2020;00:1–4. wileyonlinelibrary.com/journal/aje
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1© 2020 John Wiley & Sons Ltd
Received: 8 Octob er 2019
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Revised: 26 Ap ril 2020
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Accepted: 27 April 2020
DOI: 10.1111/aje.12749
NOTE AND RECORD
Seawater ingestion by the Mauritius flying fox
Vashist Omprasad Seegobin1 | Jean-Michel Probst1,2
1Depar tment of Bioscie nces and Ocean Stu dies, Tropi cal Island Biod iversi ty, Ecolog y and Conservation Pole of Research, University of Mauritius , Le Rédui t,
Mauritius
2Association Nature & Pat rimoine, Réuni on, Réun ion
Correspondence: Vashist Omprasad Seegob in, Tropica l Island Biodive rsity, Ecology and Conse rvation Pole of Re search, Depa rtme nt of Biosciences a nd Ocean
Studies , Univer sity of M auritius, Le Réduit, Mauriti us.
Email: voseegobin@gmail.com
1 | INTRODUCTION
Mauritius (centred around 20° 20’ S; 57° 34’ E; area 1,865 km2;
828 m maximum elevation) is a 7.8-million-year old volcanic island
with moist-to-wet tropical climate, located around 900 km east of
Madagascar in the Indian Ocean. Anthropogenic impacts started
shortly before human colonisation in 1638, which itself led to the
island becoming one of the most ecologically devastated worldwide
(Cheke & Hume, 2008; Florens, 2013; Hammond et al., 2015).
Flying foxes face threats mainly from hunting, natural habitat
transformation, invasive alien species and climate change (Vincenot,
Florens, & Kingston, 2017) which is likely to increase the occurrence
and intensit y of stochastic events such as cyclones (Elsner, Kossin, &
Jagger, 2008; Kishtawal, Jaiswal, Singh, & Niyogi, 2012; Kuleshov, Qi,
Fawcett, & Jones, 2008; Webster, Holland, Curry, & Chang, 2005).
In Mauritius, invasive alien species largely contribute to declining
native foraging habitat quality of the ‘Endangered’ Mauritius flying
fox (Pteropus niger) (Cheke & Hume, 2008; Krivek, Florens, Baider,
Seegobin, & Haugaasen, 2020). Furthermore, cyclones accompanied
with heavy rainfalls and gusts (around 100 km/hr) previously caused
60% cultivated fruit loss in Mauritius (Anon., 2012, 2015), potentially
exacerbating fruit availability for species like P. niger (McConkey,
Drake, Franklin, & Tonga, 2004; Soto-Centeno & Kurta, 2006).
Other flying fox species in Comoros, Papua New Guinea and
Philippines are known to skim over the sea before licking their
fur to obtain minerals absent from their frugivorous diet (Iudica &
Bonaccorso, 2003; Probst & Winter, 1993; Stier, 2003). However,
Thomas (1984) suggested that obligate frugivorous bats adjust nutri-
ent demands by varying amounts of eaten fruits. In Australia, Pteropus
poliocephalus frequently body dips in freshwater during days of high
temperature for cooling and rehydration (Rakotopare & Abhaya, 2019).
2 | METHODS
Eight afternoon kayak expeditions were conducted over three
weeks between February and beginning of April 2018 in the lagoon
of Pointe d’Esny, Blue Bay and from the beach (located at 20° 26'
41.56" S; 57° 42' 21.25" E). More obser vations were ma de in the bay
of Mahebourg (20° 24' 50.54" S; 57° 42' 40.60" E) and La Cambuse
(20° 27' 26.67" S; 57° 41' 38.04" E) in Februar y 2019. A Nikon D3200
DSLR camera and Sigma 100 – 300 mm telephoto lens were used to
photograph observations.
3 | RESULTS
The first observ ation was made in Februar y 2 018 in the lago on of
Pointe d’Esny at around 200 m from the coast. A Mauritius flying
fox slowly approached the water surface, within 50 m from our
position, and after several attempts clumsily succeeded in dip-
ping its lower belly part into the water and immediately licked
its wet fur before flying towards the mainland (Figure 1). Three
similar observations were made the next day and fifteen in
total over eleven days. Most observations occurred within five
weeks following heavy rainfall in Januar y (794 mm) (Statistics
Mauritius, 2018) and cyclonic conditions with gusts of 120 km/
hr (reliefweb, 2018) and after another cyclone in mid-February
2019. Each observation lasted around fifteen seconds, sometimes
occ ur ri ng on cloudy and rainy days, be tween Februar y and b egin-
ning of April, during temperature averaging 25°C, minimal wind
and calm sea conditions, and between 15:00 and 19:00. Similar
dipping behaviour throughout the year remains possible although
not reported.

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4 | DISCUSSION
Frugivorous species commonly lack certain minerals like sodium
and iron (Stier, 2003; Studier, Sevick, Ridley, & Wilson, 1994) and
often compensate through salt licking (Iudica & Bonaccorso, 2003;
Klaus & Schmidg, 1998). However, environmental factors such as
strong cyclonic winds, rainfall and temperature may influence avail-
ability (Grant, Craig, & Trail, 1997; Karr, 1976; Remis, 1997) and
quality of fruits (Sams, 1999; Worman & Chapman, 2005), alter-
ing feeding habits (Elangovan, Marimuthu, & Kunz, 1999; Kunz &
Fenton, 2005;Raghuram, Singaravelan, Nathan, & Emmanuvel, 2011).
Stochastic events like cyclones and torrential rainfall (794 mm in
January 2018 compared to 146 and 185 mm for January 2017 and
2016, respectively (Statistics Mauritius, 2018)), potentially reduce
foraging possibilities of Pteropus niger (Cheke & Dahl, 1981), beyond
consequences emanating from native foraging habitat destruction
and degradation from alien species invasion (Florens & Baider, 2013;
Florens et al., 2016; Florens, Baider, Seegoolam, Zmanay, &
Strasberg, 2017). Furthermore, invasive long-tailed macaques pop-
ulation (Macaca fascicularis) increased markedly in the last dozen of
years and the species is known to consume large numbers of na-
tive fruits, thereby depleting fruit resources otherwise available for
P. niger (Laurance & Peres , 2006). Such situation could prompt flying
foxes to explore alternative ways to supplement their diet. However,
food scarcity as a driver for seawater ingestion remains uncertain.
Se a wat e r coul d pro v ide a ri ch so u r ce of so d ium an d chl ori d e min-
erals for flying foxes (Stier, 2003). Despite fruit availability, dipping
behaviour by Pteropus niger might hel p ob tain nu trients that is sc arce
in consumed fruits. Similar dipping behaviour has been observed in
other flying fox species in the Comoros islands by P. seychellensis co-
morensis (Probst & Winter, 1993;Stobb, 1994), in the Philippines by
P. vampyrus and Acerodon jubatus (Stier, 2003), in the coas tal regions
of Papua New Guinea by P. conspicillatus, P. hypomelanus and P. t on-
ganus (Iudica & Bonaccorso, 20 03) and sug ge st ed to be either for ac-
quiring nutrient s, thermoregulation or protecting against parasites.
Other flying fox species were commonly obser ved body dipping
in freshwater during hot periods for cooling and rehydration. Pteropus
poliocephalus and P. a le c to have been seen licking their fur after
freshwater body dipping (Markus & Blackshaw, 2002; Rakotopare
& Abhaya, 2019). Commerson (Buffon, 1783) observed P. niger, in
Reunion, to occasionally dip their bodies in fresh water. However,
these behaviours, triggered by warm temperatures, seemed differ-
ent from our observations whereby dipping occurred in sea water,
late afternoons with temperature averaging 25°C, sometimes on
cloudy and rainy days.
5 | CONCLUSION
To our knowledge, this is the first record of seawater ingestion by
Pteropus niger. Some local people and fishermen who witnessed this
behaviour assumed that the species was fish-hunting, causing re-
sentment that could favour its persecution. Our observations can
help reduce incorrect beliefs and improve underst anding of the
feeding behaviour versatility, resilience ability and local adapta-
tion of P. niger to particular opportunities within its environment.
Additionally, seawater body dipping to protect flying foxes from
parasites could potentially be explored.
CONFLICT OF INTEREST
The authors declared that they do not have any potential sources of
conflict of interests.
FIGURE 1 (a) A Mauritius flying fox
approaching the seawater sur face, (b)
dipping it s lower body part into it and (c)
licking the salty water from its wet fur
before (d) flying back to the mainland
(a) (b)
(c) (d)

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DATA AVA ILAB ILITY STATE MEN T
The data that support the findings of this study are openly available
in ‘Dryad’ at https://doi.org/10.5061/dryad.1c59z w3rc (Seegobin,
2019).
ORCID
Vashist Omprasad Seegobin https://orcid.
org/0000-0002-6334-4105
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How to cite this article: Seegobin VO, Probst J-M. Seawater
ingestion by the Mauritius flying fox. Afr J Ecol. 2020;00:1–4.
https://doi .org /10.1111/aje.12749