diff --git a/src/wrappers/SpecimenWrapper.js b/src/wrappers/SpecimenWrapper.js
index 805ef26..acbdf1e 100644
--- a/src/wrappers/SpecimenWrapper.js
+++ b/src/wrappers/SpecimenWrapper.js
@@ -57,7 +57,7 @@ class SpecimenWrapper {
   static fromOccurrenceID(occurrenceID, basisOfRecord = 'PreservedSpecimen') {
     // Copy the occurrence ID so we can truncate it if necessary.
     let occurID = occurrenceID;
-    if (occurID.startsWith('urn:catalog:')) occurID = occurID.substr(12);
+    if (occurID.startsWith('urn:catalog:')) occurID = occurID.substring(12);
 
     // Prepare the specimen.
     const specimen = {