r 



THE AGRTCULTUr.AL NEWS. 



Mat :?. 1919. 



THE FOOD OF THE MONGOOSE IN 



TRINIDAD. 



!■! are.ent nuuibci oc tLe hji/utvi or n,- ly j,r.. „ ,. ..,' 



Aj'-.c:'';--: T.:m.Uv: .""« '/'■'"." (Vol. XVII part i, 



p it.:, there i.ii.i*ar> m rtcticle uiuler the above title by 



>lr (.'. B. William.-. M.A, F.K.S.. Kn.omologistuvLhaige of 



frcgip-pper Investigatioi:.-. 



This article recc'nis the examination of ISO stomachs ot 

 luODgccce taken througuottt a period of one year, and affords 

 much more information on this important subject than has 

 been available hitLerto. 



In the introduction the author mention.* that the 

 <,ae*tion ha.s been freduently raised as to the responsibility 

 of the mongoose l.jr the prevalence of the froghopper which 

 t IS been a serious pest of sugarcane in Trinidad . 



An article on rat^ a. d mongoose in the \N e.st Indies 

 appeared in the A^irlcnUwal Ntuf, November 2, 1918. 

 In thi< it was shown that in certain of the West Indian 

 inlands the monsoose is held to be largely responsible f.>r the 

 ..ut .reak of certain injects as pests of crops, owing to its action 

 in killing laige numbers of beneficial forms of animal life. 



Mr." Williams refers to the need which he found of 

 information as to these matter.', and the ab>ence of any 

 sufficiently accurate work on the subject on which to base 

 conclusions. Consequently, in order to provide the necessary 

 =nf..rraation, dissections of mongoose stomachs were begun in 

 October 1917, and carried on as fully as possible until 

 September 191S. In all. ISO stomachs were e.xanuned, of 

 which fourteen were empty. Of the remaining l(i6. eighty- 

 five \/e e obtained in the dry season (February to May), and 

 eighty one in the wet season (-lune to .(aniu.ry) — January 

 19L- was excep'ioially wet. 



The information obtained lias provided a basis for com- 

 paring the good done by the mongoose, and the harm that 

 ma )e charged against it. After a list giving a detailed 

 ana'ly^'isof the contents of each of the stoniaclis e.xainincd, 

 with remarks on the various foods contained in them the 

 write: sutnmarizcs on the one hand the damage, and on tLe 

 other, ihe good that may be attributed to the mongoose, as 

 follow;; — 



•Credit: Twenty eight rats, about fiOn in jniious insects 

 and three crabs. 



'l>ebit: Twenty-six birds, seventeen li/anls. twenty- 

 nine frogs and toads, foriy-four useful insects, and forty -lour 



spiders, 



'I'rom the above it is possible to draw certain conclusions 

 of which the foUowii^g are perhaps the most importan':— 



'(i) The mongoose is neiiher entirely harintul. nor on tlie 

 other hand, entirely beneficial. 



■(ii) The damage <lone li> wild bird.s is probably coni- 

 nl.-tely ff^'eet by the r.umber of rats destroyed, which would 

 themselvfs have dest^yrd many of the tree- living birds 

 which the mongoo.«e cannot reach. 



■(ill) The desirnrtion of lizard*, frogs, and toad.s is 

 o„lv partly offset by the numbers of injurious insects des- 

 troyed and tliere is little doubt that the presence of the 

 nioBgo'o-e in larjje numbers in a district will m this way have 

 «n unwelcomi^ ellect on the numbers of in.secta present. 



(iv) Th<' CI. mplee extermination of the niongoo.se wonl.l 

 i.rooably lead to a recrudescence of the damage ranfml by 

 r.its which, in hona; conntriF.s, is a ferious item 



'The variations nf forvl. according to season and locality, 

 i,ie »et out in a table, the information in whi'h i.s summarized 



fus follows:— , . , , 



h,-'iii''i--'(\^ Twenty two rats wen.- toun.l in 11> 

 MoTmct"^ on the sugar estates as coinp.ircd with thTt- in 



forty-eight stomachs in the cacao districts. This may 

 he due to there being a greater number of rats in the sugar 

 district, but greater facilities for escape afforded to the 

 rats by the trees in the cacao districts will also aftect the 

 result. 



'(iii The total number of birds is relatively higher in the 

 cacao districts, but this is entirely due to the greater number 

 of domestic fowls, which are much commoner round the 

 numerous small hoasi^of the cacao planter than on the .sugar 

 estates, 



'(iii» The number of frogs and toads destroyed is relatively 

 much larger in the sugar than in the cacao districts. 



'(iv) The number of snakes destroyed is relatively higher 

 ill the cacao distrcts . 



Season. --'{\\ The' number of rats destroyed was more 

 than twice as great in the dry season as in the wot. 



(ii) The number of snakes destroyed was more than 

 three times as great in the wet season as in the dry seison. 



(iii) The number of frogs and toads destroyed was 

 nearly twice as great in tiie wet season as in the dry. 



(iv) The number of adult Lameliicorn beetles (indudini; 

 "hardbacks") was more than three times as great in the wet 

 season as in the dry. This is easily explained by the fact 

 that most of these hatch out in the wet season. < )n the 

 other hand, the number of Cavabid larvae was greater in the 

 dry season. 



'(v) The number of spiders destroyed was greater in the- 

 wet season. 



(vi) Of the sixteen centipedes destroyed, only one was 

 taken in the dry season, and that one in February after a 

 wet .January.' 



A comparison is given of the food of the mongonse in 

 t*ie northern and in the southern districts. In the northera 

 district this aniiualhas been established and widely distributed 

 for many years, but it has only recently invaded the southern 

 part of the island. 



It was held that if the :iiongoosc durins; its residence in 

 the island had had any effect on the relative numbers of the 

 animals on which it preys it might be possible to trace such aa 

 etlect by a c.'^mparison of its food in the distr'ct where it lus 

 been established for many years with tho.sc into which it has- 

 but recently spread. 



The comparison has therefore been made of the contents 

 of thirty-six .>-iomachs of mongoose killed in the northern 

 districts with those of forty stomachs obtained from the south. 



An inspection of the analysis of the stomach contentjs. 

 shows the following points of interest: — 



'(i) The number of rats destroyed is much larger in the 

 southern (newly infested) district than in the northern. 



'Xo other oMplanation of this appears to be pos.^ibU' but 

 that the long presence of the mongoose in the nortlurn districts 

 his reduced the number of rats available for food. 



'(ii) The iiumb» r of birds destroyed is gicater in the- 

 southern district ; in fact no birds were found in the stomaclis. 

 of mongoose taken a'. Canmi. 



it must be noted in this connexion that ( aroni estate- 

 in the muth i.i a laive Hat area very bare of trees and bush. 

 The soiitlicrn estates are more broken u|) by other cultivation 

 and have in.yeneral a greater nuiubev of trees. Allowing for 

 this, it is .nill pi.PsibK. that the tiuures indicate thai the 

 numbtr of birds in the northern di-^t'lrt h is bi-cn n- luc,.,! (jy 

 the mongoose. 



•(iii) T'he iiuuiijcr of liz;uds 'xwd «nake~ In siiyhtlv 

 greater in the iinrthein district tlian in the s.iuth-Tii 



