Remember the ‘blueberry jam’ civet scats that are quite commonly seen?
These ‘blueberry jam’ civet scats consist of the fruit peels and seeds of the fishtail palm! From the diet study that I have conducted, the dominant fruit with seeds present in the scats was the fishtail palm Caryota mitis. This is consistent with other findings which pointed to Caryota spp. being a common food item in the diet of the common palm civet (Bartels, 1964; Corlett, 1998; Xu & Sivasothi, 2010). Thus, it is not without reason that civet scats that were easily recognised by the public were those that contained fishtail palm seeds!
The fishtail palm can be easily recognised by its leaves which are shaped like a fish tail which gave it its name.
The fruit of the fishtail palm is 1.5 cm in diameter and contains a large seed (1.1 cm), which has a thin fleshy mesocarp containing calcium oxalate (Sento, 1971). The fruits are purplish red when riped (DO NOT touch them with your bare hands! The calcium oxalate will cause serious itchness!). By swallowing the indigestible seeds, the civet would obtain relatively less nutrients as compared to a berry of similar fruit size. (Photo of a civet in a fishtail palm)
So, is the fishtail palm the favourite food of the common palm civets?
We do not know the preference of the common palm civet currently, however, what we hypothesis is that what the fishtail palm lacks in nutrition, it makes up in availability. The fishtail palm is unique in its phenology as once it reaches maturity, it will begin producing inflorescences. Infructescences appear sequentially from top to bottom over several years and represent a productive food source for the common palm civet (Mahabale & Shirke, 1968; Llamas, 2003).
Mature plants appear to be fruiting all year round whereas other species found in this diet study such as the tembusu Fagraea fragrans, only fruit seasonally (Polunin, 1987). Indeed Rabinowitz (1991) reported that while fruits were eaten by the common palm civet whenever available, fruit availability is variable spatially and temporarily. This consumption of fishtail palm fruit may represent the best strategy in the absence of a consistent and more nutritious food source.
This diet dependency suggests a key stone species role for the fishtail palm in secondary forests. The plant also may be providing food for other animals all year round such as long tailed macaques, squirrels and birds such as the Asian Koel (Eudynamys scolopaceus) (Bird Ecology Study Group, 2007) which are known to feed on at least some part of the fishtail palm. BESG has also reported that birds such as the Lineated Barbet (Megalaima lineata hodgsoni), Yellow Vented Bulbul (Pycnonotus goiavier) and the Pink-necked Green Pigeon (Treron vernans) also feed on these fruits!
What do we know about the fishtail palm currently?
A native species, this plant is now planted as an ornamental tree for urban landscaping and is readily available. It may be an important plant in rehabilitating degraded secondary forests in conjunction with other plantings and introductions of frugivores such as the common palm civets to aid in dispersal. However, relatively little is actually known about the ecology of the fishtail palm (Raich, 1990) and a study should be initiated in the near future.
So, next time when you are in the bus or car, look out of the window and try to spot these plants! I am sure they will pop out at you now and remember, our last native urban carnivore loves these fruits (at least to some extent)!