$ cat -te tt1.txt
camel^I42$
pearl^I94$
dromedary^I69$

$ cat -te tt2.txt
camel^I8$
hello^I12345$
dromedary^I1$

$ perl -MText::CSV_XS=csv -wE'csv(in=>*ARGV,sep=>"\t",out=>undef,on_in=>sub{$x{$_[1][0]}+=$_[1][1]});printf"%-20s %6d\n",$_,$x{$_}for sort keys%x' tt?.t
camel                    50
dromedary                70
hello                 12345
pearl                    94